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takeup_workingpaper.Rmd
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takeup_workingpaper.Rmd
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---
title: |
| Social Signaling and Prosocial Behavior
| Experimental Evidence in Community Deworming in Kenya^[This study was funded by the Children's Investment Fund Foundation and implemented by Evidence Action. We thank Guillaume Kroll, the study's project manager; Arthur Baker, our research assistant; Doris Njomo and Rosemary Musuva for their qualitative research input during the study's pilot; Carol Nekesa and her implementation and data collection team; Ned Augenblick, Edward Miguel and Stefano DellaVigna for their research advice; Supreet Kaur, Dmitry Taubinsky, Seema Jayachandran, Nancy Qian and seminar participants at Berkeley, Northwestern Rookiefest, Oxford CSAE Conference 2018 and PacDev 2018 for helpful discussions and feedback; and Karen Levy and Grace Hollister for their advice and support. We received Internal Review Board clearance from the Kenya Medical Research Institute and the University of California Berkeley. The study pre-analysis plan was registered with the American Economic Association registry (<https://www.socialscienceregistry.org/trials/1643/history/17782>).]
date: "December 2020"
subtitle: "Please find the latest version of the paper [here](https://github.com/karimn/takeup/blob/master/takeup_workingpaper.pdf)"
author:
- Anne Karing^[Princeton University, `[email protected]`.]
- Karim Naguib^[`[email protected]`.]
output:
pdf_document:
number_sections: yes
fig_caption: yes
keep_tex: no
pandoc_args: "commonrmd.yaml"
includes:
in_header: takeup_workingpaper_header.sty
abstract: "Can social image concerns motivate adults to internalize health externalities? In collaboration with the Kenyan Government, we implement a new community program that offers free deworming treatment to 200,000 adults and emphasizes the public good aspect of deworming. Importantly, we randomize the introduction of two types of social signals in the form of colorful bracelets and ink applied to the thumb. The bracelets and ink allow adults to signal that they contributed to protecting their community from worms. Further, we exogenously vary the travel distance to treatment locations. To separate reputational utility from private consumption utility and social learning/salience, we combine experimental identification with a structural model's non-experimental identification. We find that (1) bracelets as signals increase deworming take-up by roughly 13 percent, net the private consumption and learning/salience effects; (2) there is no detectable effect for the ink signal, which we attribute to its private disutility which outweighs any reputational utility from signaling; (3) adults are highly sensitive to distance; (4) the rate-of-change in take-up in response to distance is potentially high, playing an important role in mitigating the effect of increasing costs. Detailed survey data on first and second-order beliefs shed light on the underlying mechanism: signals reduce information asymmetries, and adults are more likely to think that others have information about their deworming decision."
nocite: |
@R
urlcolor: blue
bibliography: /home/karim/Documents/library.bib
---
<!-- abstract: "Can social image concerns motivate adults to internalize health externalities? In collaboration with the Kenyan Government, we implement a new community program that offers free deworming treatment to 200,000 adults and emphasizes the public good aspect of deworming. Importantly, we randomize the introduction of two types of social signals in the form of colorful bracelets and ink applied to the thumb. The bracelets and ink allow adults to signal that they contributed to protecting their community from worms. To separate social signaling preferences from reminder and learning effects, we offer free text messages to a random subset of adults. Further, we exogenously vary the travel distance to treatment locations. We find that (1) bracelets as signals increase deworming take-up by 24 percent, outperforming a material incentive; (2) the effects are not due to pure reminder or learning effects; (3) there is no detectable effect for the ink signal, which we attribute to its lower visibility; (4) adults are highly sensitive to distance and both signaling treatments have a larger impact on take-up at far distances. The latter finding is consistent with the theoretical prediction that signaling returns increase as signals become more informative. Detailed survey data on first and second-order beliefs shed light on the underlying mechanism: signals reduce information asymmetries, and adults are more likely to think that others have information about their deworming decision." -->
\newpage
```{r workingpaper-setup, include=FALSE}
library(plyr)
library(magrittr)
library(lubridate)
library(forcats)
library(broom)
library(ggrepel)
library(ggmap)
library(ggstance)
library(gridExtra)
library(cowplot)
library(rgeos)
library(sp)
library(rgdal)
library(knitr)
library(modelr)
library(car)
library(rstan)
library(tidyverse)
library(latex2exp)
library(econometr)
source(file.path("rct-design-fieldwork", "takeup_rct_assign_clusters.R"))
source("analysis_util.R")
knitr::read_chunk("analysis_util.R", labels = "analysis-util")
knit_hooks$set(document = function(x) {sub('\\usepackage[]{color}', '\\usepackage[table,dvipsnames]{xcolor}', x, fixed = TRUE)})
read_chunk(purl("takeup_analysis2.Rmd"))
options(dplyr.show_progress = FALSE, digits = 4, knitr.kable.NA = '')
opts_chunk$set(echo = FALSE, warning = FALSE,
cache = TRUE, cache.path = "takeup_workingpaper-cache/",
fig.path = "takeup_workingpaper-fig/", fig.align = "center")
```
```{r proj4}
wgs.84 <- "+proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0"
kenya.proj4 <- "+proj=utm +zone=36 +south +ellps=clrk80 +units=m +no_defs"
```
```{r model-versions}
static_fit_version <- "param_static_2962857" # Name matched and SMS
dyn_fit_version <- "param_dynamic_2330870" # Strata level only with cluster RE
```
```{r ggplot-theme, cache=FALSE}
theme_set(theme_minimal() +
theme(legend.position = "bottom",
panel.border = element_rect(colour = "darkgrey", fill = NA)))
```
```{r load-experiment-design-data}
rct.schools.data <- read_rds(file.path("data", "takeup_rct_schools.rds"))
rct.cluster.selection <- read_rds(file.path("data", "rct_cluster_selection_2.0.rds"))
cluster.strat.data <- read_rds(file.path("data", "takeup_processed_cluster_strat.rds"))
load(file.path("data", "takeup_village_pot_dist.RData"))
```
```{r load-analysis-data}
load(file.path("data", "analysis.RData"))
standardize <- as_mapper(~ (.) / sd(.))
unstandardize <- function(standardized, original) standardized * sd(original)
nosms_data <- analysis.data %>%
filter(sms.treatment.2 == "sms.control") %>%
left_join(village.centers %>% select(cluster.id, cluster.dist.to.pot = dist.to.pot),
by = "cluster.id") %>%
mutate(standard_cluster.dist.to.pot = standardize(cluster.dist.to.pot)) %>%
group_by(cluster.id) %>%
mutate(cluster_id = cur_group_id()) %>%
ungroup()
monitored_nosms_data <- analysis.data %>%
filter(mon_status == "monitored", sms.treatment.2 == "sms.control") %>%
left_join(village.centers %>% select(cluster.id, cluster.dist.to.pot = dist.to.pot),
by = "cluster.id") %>%
mutate(standard_cluster.dist.to.pot = standardize(cluster.dist.to.pot)) %>%
group_by(cluster.id) %>%
mutate(cluster_id = cur_group_id()) %>%
ungroup()
analysis_data <- monitored_nosms_data
```
```{r load-beliefs-model-results}
beliefs_results <- read_rds(file.path("data", "stan_analysis_data", "secobeliefs_results.rds")) %>%
map(mutate, across(starts_with("assigned.treatment"), fct_relabel, str_to_title)) %>%
map(mutate, across(starts_with("assigned.treatment"), fct_relevel, "Bracelet", "Ink", "Calendar", "Control"))
```
```{r load-processed-dist-fit, cache=TRUE}
load(file.path("data", "stan_analysis_data", "dist_fit29.RData"))
# If using cmdstanr
dist_fit %<>%
map_if(is.character, read_rds)
if (has_name(dist_fit, "value")) {
dist_fit_warnings <- dist_fit$warning
dist_fit %<>%
list_modify(!!!.$value, value = NULL, warning = NULL)
}
load(file.path("temp-data", "processed_dist_fit29.RData"))
dist_fit_data %<>%
left_join(distinct(., model) %>%
mutate(model_color = RColorBrewer::brewer.pal(n(), "Dark2")),
by = "model") %>%
bind_rows(
filter(., fct_match(model, c("STACKED", "STRUCTURAL_STACKED"))) %>%
mutate(fit_type = factor("prior-predict")) %>%
mutate_at(vars(starts_with("est_takeup")), map, mutate_at, vars(starts_with("per_"), mean_est), ~ per_0.5) # Add fake prior-predict so plots align/dodge properly
)
dist_fit_data %<>%
select(fit_type, model, model_name, model_type, model_color, starts_with("stacking_weight"), contains("elpd"), starts_with("est"), contains("y_rate_of_change")) %>%
mutate_if(~ is.list(.x), map_if, ~ !is_empty(.x), ~ select(.x, -one_of("iter_data")))
plot_estimands <- function(.data, y, include_prior_predict = FALSE) {
plot_pos <- position_dodgev(height = 0.8)
ggplot_obj <- if (include_prior_predict) {
ggplot(.data, aes(x = per_0.5, y = {{ y }}, group = model)) +
ggstance::geom_linerangeh(aes(xmin = per_0.05, xmax = per_0.95, group = model), alpha = 0.15, fatten = 3, size = 10, position = plot_pos, data = . %>% filter(fct_match(fit_type, "prior-predict"))) +
ggstance::geom_linerangeh(aes(xmin = per_0.05, xmax = per_0.9, group = model), alpha = 0.1, fatten = 3, size = 6, position = plot_pos, data = . %>% filter(fct_match(fit_type, "prior-predict"))) +
ggstance::geom_linerangeh(aes(xmin = per_0.05, xmax = per_0.5, group = model), alpha = 0.1, fatten = 3, size = 4, position = plot_pos, data = . %>% filter(fct_match(fit_type, "prior-predict"))) +
NULL
} else {
ggplot(.data, aes(x = per_0.5, y = {{ y }}, group = model))
}
ggplot_obj +
ggstance::geom_linerangeh(aes(xmin = per_0.25, xmax = per_0.75, color = model), alpha = 0.4, size = 3, position = plot_pos, data = . %>% filter(fct_match(fit_type, "fit"))) +
ggstance::geom_crossbarh(aes(x = per_0.5, xmin = per_0.1, xmax = per_0.9, color = model), fatten = 0, size = 0.4, width = 0.5, position = plot_pos, data = . %>% filter(fct_match(fit_type, "fit"))) +
ggstance::geom_linerangeh(aes(xmin = per_0.05, xmax = per_0.95, color = model), size = 0.4, position = plot_pos, data = . %>% filter(fct_match(fit_type, "fit"))) +
# ggstance::geom_crossbarh(aes(xmin = per_0.25, xmax = per_0.75, color = model), size = 0.7, alpha = 0.05, width = 0.25, position = plot_pos, data = . %>% filter(fct_match(fit_type, "fit"))) +
# ggstance::geom_crossbarh(aes(xmin = per_0.1, xmax = per_0.9, color = model), size = 0.7, width = 0.4, position = plot_pos, data = . %>% filter(fct_match(fit_type, "fit"))) +
# ggstance::geom_linerangeh(aes(xmin = per_0.05, xmax = per_0.95, color = model), size = 0.7, fatten = 3, size = 0.8, position = plot_pos, data = . %>% filter(fct_match(fit_type, "fit"))) +
geom_point(aes(x = mean_est, color = model), position = plot_pos, data = . %>% filter(fct_match(fit_type, "fit"))) +
geom_point(aes(x = mean_est), color = "white", size = 0.75, position = plot_pos, data = . %>% filter(fct_match(fit_type, "fit"))) +
geom_vline(xintercept = 0, linetype = "dotted") +
scale_color_manual("Model",
values = select(dist_fit_data, model, model_color) %>% deframe(),
labels = dist_fit_data %>% select(model, model_name) %>% deframe(), aesthetics = c("color", "fill")) +
labs(
caption = #"Dotted line range: 98% credible interval.
"Line range: 90% credible interval.
Outer box: 80% credible interval. Inner box: 50% credible interval.
Thick vertical line: median. Point: mean."
) +
theme(legend.position = "top", legend.direction = "vertical") +
guides(color = guide_legend(ncol = 3)) +
NULL
}
```
```{r estimands, cache=FALSE}
bracelet_vs_control_ate_ci <-
str_credible_interval(dist_fit_data, "STACKED", est_takeup_te,
fct_match(assigned_treatment_left, "bracelet"),
fct_match(assigned_treatment_right, "control"),
mu_assigned_treatment_left == assigned_treatment_left,
mu_assigned_treatment_right == assigned_treatment_right,
is.na(assigned_dist_group_left), is.na(assigned_dist_group_right),
prob = 0.8)
bracelet_vs_calendar_close_ate_ci <-
str_credible_interval(dist_fit_data, "STACKED", est_takeup_te,
fct_match(assigned_treatment_left, "bracelet"),
fct_match(assigned_treatment_right, "calendar"),
mu_assigned_treatment_left == assigned_treatment_left,
mu_assigned_treatment_right == assigned_treatment_right,
fct_match(assigned_dist_group_left, "close"), fct_match(assigned_dist_group_right, "close"),
prob = 0.8)
bracelet_vs_calendar_far_ate_ci <-
str_credible_interval(dist_fit_data, "STACKED", est_takeup_te,
fct_match(assigned_treatment_left, "bracelet"),
fct_match(assigned_treatment_right, "calendar"),
mu_assigned_treatment_left == assigned_treatment_left,
mu_assigned_treatment_right == assigned_treatment_right,
fct_match(assigned_dist_group_left, "far"), fct_match(assigned_dist_group_right, "far"),
prob = 0.8)
bracelet_vs_control_struct_ate_ci <-
str_credible_interval(dist_fit_data, "STRUCTURAL_STACKED", est_takeup_te,
fct_match(assigned_treatment_left, "control"),
fct_match(assigned_treatment_right, "control"),
fct_match(mu_assigned_treatment_left, "bracelet"),
fct_match(mu_assigned_treatment_right, "control"),
is.na(assigned_dist_group_left), is.na(assigned_dist_group_right),
prob = 0.8)
calendar_vs_control_ate_ci <-
str_credible_interval(dist_fit_data, "STACKED", est_takeup_te,
fct_match(assigned_treatment_left, "calendar"),
fct_match(assigned_treatment_right, "control"),
mu_assigned_treatment_left == assigned_treatment_left,
mu_assigned_treatment_right == assigned_treatment_right,
is.na(assigned_dist_group_left), is.na(assigned_dist_group_right),
prob = 0.8)
calendar_vs_control_struct_ate_ci <-
str_credible_interval(dist_fit_data, "STRUCTURAL_STACKED", est_takeup_te,
fct_match(assigned_treatment_left, "control"),
fct_match(assigned_treatment_right, "control"),
fct_match(mu_assigned_treatment_left, "calendar"),
fct_match(mu_assigned_treatment_right, "control"),
is.na(assigned_dist_group_left), is.na(assigned_dist_group_right),
prob = 0.8)
ink_vs_control_ate_ci <-
str_credible_interval(dist_fit_data, "STACKED", est_takeup_te,
fct_match(assigned_treatment_left, "ink"),
fct_match(assigned_treatment_right, "control"),
mu_assigned_treatment_left == assigned_treatment_left,
mu_assigned_treatment_right == assigned_treatment_right,
is.na(assigned_dist_group_left), is.na(assigned_dist_group_right),
prob = 0.8)
ink_vs_control_struct_ate_ci <-
str_credible_interval(dist_fit_data, "STRUCTURAL_STACKED", est_takeup_te,
fct_match(assigned_treatment_left, "control"),
fct_match(assigned_treatment_right, "control"),
fct_match(mu_assigned_treatment_left, "ink"),
fct_match(mu_assigned_treatment_right, "control"),
is.na(assigned_dist_group_left), is.na(assigned_dist_group_right),
prob = 0.8)
bracelet_vs_control_ate_mean <-
str_mean(dist_fit_data, "STACKED", est_takeup_te,
fct_match(assigned_treatment_left, "bracelet"),
fct_match(assigned_treatment_right, "control"),
mu_assigned_treatment_left == assigned_treatment_left,
mu_assigned_treatment_right == assigned_treatment_right,
is.na(assigned_dist_group_left), is.na(assigned_dist_group_right),
round_by = NA)
bracelet_vs_calendar_ate_mean <-
str_mean(dist_fit_data, "STACKED", est_takeup_te,
fct_match(assigned_treatment_left, "bracelet"),
fct_match(assigned_treatment_right, "calendar"),
mu_assigned_treatment_left == assigned_treatment_left,
mu_assigned_treatment_right == assigned_treatment_right,
is.na(assigned_dist_group_left), is.na(assigned_dist_group_right),
round_by = NA)
control_level_mean <-
str_mean(dist_fit_data, "STACKED", est_takeup_level,
fct_match(assigned_treatment, "control"),
mu_assigned_treatment == assigned_treatment,
is.na(assigned_dist_group),
round_by = NA)
control_close_level_mean <-
str_mean(dist_fit_data, "STACKED", est_takeup_level,
fct_match(assigned_treatment, "control"),
mu_assigned_treatment == assigned_treatment,
fct_match(assigned_dist_group, "close"),
round_by = NA)
bracelet_vs_calendar_ate_ci <-
str_credible_interval(dist_fit_data, "STACKED", est_takeup_te,
fct_match(assigned_treatment_left, "bracelet"),
fct_match(assigned_treatment_right, "calendar"),
mu_assigned_treatment_left == assigned_treatment_left,
mu_assigned_treatment_right == assigned_treatment_right,
is.na(assigned_dist_group_left), is.na(assigned_dist_group_right),
prob = 0.8)
control_close_level_mean <-
str_mean(dist_fit_data, "STACKED", est_takeup_level,
fct_match(assigned_treatment, "control"),
mu_assigned_treatment == assigned_treatment,
fct_match(assigned_dist_group, "close"),
round_by = NA)
control_distance_diff_mean <-
str_mean(dist_fit_data, "STACKED", est_takeup_te,
fct_match(assigned_treatment_left, "control"),
fct_match(assigned_treatment_right, "control"),
fct_match(assigned_dist_group_left, "far"),
fct_match(assigned_dist_group_right, "close"),
round_by = NA)
control_distance_diff_ci <-
str_credible_interval(dist_fit_data, "STACKED", est_takeup_te,
fct_match(assigned_treatment_left, "control"),
fct_match(assigned_treatment_right, "control"),
fct_match(assigned_dist_group_left, "far"),
fct_match(assigned_dist_group_right, "close"),
prob = 0.8)
bracelet_distance_diff_diff_ci <-
str_credible_interval(dist_fit_data, "STACKED", est_takeup_dist_te,
fct_match(assigned_treatment_left, "bracelet"),
fct_match(assigned_treatment_right, "control"),
prob = 0.8)
ink_distance_diff_diff_ci <-
str_credible_interval(dist_fit_data, "STACKED", est_takeup_dist_te,
fct_match(assigned_treatment_left, "ink"),
fct_match(assigned_treatment_right, "control"),
prob = 0.8)
bracelet_distance_diff_diff_per_0.25 <-
str_percentile(dist_fit_data, "STACKED", est_takeup_dist_te,
fct_match(assigned_treatment_left, "bracelet"),
fct_match(assigned_treatment_right, "control"),
per = 0.25)
ink_distance_diff_diff_per_0.25 <-
str_percentile(dist_fit_data, "STACKED", est_takeup_dist_te,
fct_match(assigned_treatment_left, "ink"),
fct_match(assigned_treatment_right, "control"),
per = 0.25)
```
# Introduction
<!-- Motivation and research question -->
Externalities play an important role in many health behaviors. Prominent examples are deworming, smoking, open defecation and vaccination. Individuals frequently undervalue the social costs and benefits of their actions and under-invest in public goods like deworming. There is an extensive theoretical literature on the role of social signaling and image concerns [@Bernheim1994; @Benabou2006;@Benabou2012a]. Recent field experiments show that social image concerns affect important behaviors, such as consumption, the decision to vote, and student effort [@Dellavigna2017; @Bursztyn2017a; @Bursztyn2015]. However, empirical evidence from field settings in low-income countries is scarce. Developing countries are a particularly important context, since formal enforcement mechanisms are often missing to produce efficient contributions to public goods and signaling incentives could be an inexpensive substitute.^[For example, the United States and Germany have laws that require children to be immunized in order to attend daycare. There is an extensive literature showing the effectiveness of material and financial incentives in encouraging positive health behaviors [@Thornton2008; @Banerjee2010;@Sato2015] However, governments often raise concerns about the scalability and financial sustainability of these incentives.] We chose community deworming, as an empirical setting, to manipulate social signaling concerns. Deworming is a public good for which most of its benefits accrue through reduced disease transmission [@Miguel2004]. Worm infections in adults present a large disease burden as they lead to continuous reinfections among children [@Anderson2013;@Anderson2014;@Truscott2014;@Njenga2011]. In this paper, we ask two questions: Can social signals increase adults' willingness to take up deworming treatment? To what extent do differences in peer take-up affect the reputational returns of signals?
<!-- Experimental design and identification -->
We answer these questions by implementing a large-scale field experiment that is closely tied to Bénabou and Tirole's theory of social signaling [-@Benabou2006;-@Benabou2012a]. In collaboration with the Kenyan Government, we launch a new community deworming program where health volunteers offer free deworming treatment to over 200,000 adults at central locations (instead of through a traditional door-to-door campaign) over a period of 12 days. We inform adults, prior to the program, about the health benefits of deworming with an explicit emphasis on the public good aspect of treatment. Our main experimental manipulations are (i) to increase the observability of deworming decisions and (ii) to vary the distance that adults have to travel to receive treatment.
Specifically, we introduce two social signals in the form of a colorful bracelet and ink applied to adults' thumbs, both of which are given to adults upon coming for deworming treatment. As a third treatment, we introduce a private material incentive in the form of a one-page wall calendar that allows us to hold constant the consumption value of the bracelet. We randomize 144 treatment locations and their surrounding communities into the ink, bracelet and calendar treatments or a control group where no incentive is given.
In addition, we randomly assign the distance communities must cover in order to reach their closest treatment location allowing us to exogenous vary the cost of deworming. Communities are assigned to be either _close_ (less than 1.25 kilometers) or _far_ (between 1.25 and 2.5 kilometers) in terms of distance to deworming treatment. This cost manipulation is critical to our approach in learning about how signaling responds to changes in cost; reputational returns change as an action is perceived as more or less difficult to do.
Our goal is to estimate the treatment effect of social signaling. The experiment identifies the combined effect of social signaling, salience and social learning effects. To separately identify the extent to which deworming decisions are driven by a desire to signal, we use two approaches. First, we use the calendar treatment arm to eliminate the private consumption value from the bracelets' effect. Second, we use a structural model reflecting the theoretical model's data generating process, permitting us to estimate counterfactuals not possible to observe in the experiment, namely holding constant private consumption utility while manipulating the ability to signal.
<!-- Talk about SMS if the model is added back -->
<!-- The cluster randomization identifies the combined effect of social signaling, salience and social learning effects. To separately identify the extent to which deworming decisions are driven by a desire to signal, we offer free text messages to a small random subset of adults in each of the study communities. The text messages (a) remind individuals of the availability of deworming and (b) provide information about the share of adults that have come for deworming in their community. Lastly, to exogenously vary the cost of deworming, we randomly assign communities to close (less than 1.25 kilometers) or far (between 1.25 and 2.5 kilometers) walking distances to treatment locations. The distance randomization allows us to exogenously shift the level of deworming take-up at community level. -->
<!-- Summary of results / Data collected -->
We monitor deworming decision of 38,000 adults at the points of treatment, avoiding the reliance on self-reported data on take-up. In addition, we collect detailed survey data on adults' knowledge about deworming, social norm concerns, and first- and second-order beliefs to speak to the mechanisms underlying social signaling. We show that bracelets as signals increased the visibility of deworming decisions, compared to the ink and calendar treatments, and reduced perceived information asymmetries. Adults were significantly more likely to think that others had knowledge about their own deworming decision. The survey data further reveals that adults have a limited understanding of the externalities from deworming, and think of it as "the right thing to do" for a person that looks after their own health.
For our analysis we build three models to investigate different aspects of the data generating process. To estimate these models we use hierarchical Bayesian statistical models. One of the models is a reduced-form model that uses the experimental intervention to identify treatment effects and the two other models are parametric models that rely on structural assumptions to identify unobservable counterfactuals. Our Bayesian statistical analysis allows for the flexible construction of statistical models accounting for the complexity of the experiment in terms of the population studied (stratification) and experimental treatment; it allows us to conduct a large number of comparisons over the four experiments, using regularization; it allows us to more efficiently learn from the data using partial pooling; and finally it allows us to efficiently average treatment effects over the three statistical models used [@Imbens2015;@Gelman2013a;@stan;@Yao2018].^[Reduced form OLS regression analysis plots are included in Appendix A for comparison.]
<!-- TODO summarize results -->
Averaging the three models' estimation, we find that bracelets have the strongest effect on deworming take-up, with 80% credible interval of `r bracelet_vs_control_ate_ci` percentage points increase, and in terms of (posterior) averages, a `r round(bracelet_vs_control_ate_mean/control_level_mean, 3) * 100` percent change. When compared against the calendar treatment we still see social effect of `r bracelet_vs_calendar_ate_ci` percentage points, a `r round(bracelet_vs_calendar_ate_mean/control_level_mean, 3) * 100` percent increase. For the second signaling treatment, ink, we found no detectable effect: our analysis did not yield an informative credible interval. Averaging over the two structural models, we find that the pure social signaling treatment effect of bracelets, compared to the control arm, is `r bracelet_vs_control_struct_ate_ci` percentage points, and for the ink treatment `r ink_vs_control_struct_ate_ci` percentage points. Ink does have a similar social signaling effect to bracelets, however, it appears to be cancelled out by its private disutility. Calendars are found to have a `r calendar_vs_control_ate_ci` percentage points effect combining all models, and `r calendar_vs_control_struct_ate_ci` percentage points social signaling effect. Both the disutility of ink and the signaling effect of calendars were unexpected. With respect to the effect of signals in response to increasing costs, we do find that all the signaling treatments have a significantly different rate-of-change from the control arm, over the observed cost range of the experiment, albeit with relatively high uncertainty. This points to the possibility that signaling was able mitigate the negative effect of increasing costs (distance to deworming treatment).
<!-- We then build a static and dynamic hierarchical Bayesian model to impute the counterfactuals necessary to estimate the partial effect of social signaling on deworming take-up decisions. Our Bayesian analysis allowed for the flexible construction of statistical models accounting for the complexity of the experiment in terms of the population studied and experimental treatment.[^why-bayes] This allowed us to manage the large number of treatment comparisons, using regularization, while allowing us to efficiently learn from the data using partial pooling [@Imbens2015;@Gelman2013a;@stan].^[Reduced form OLS regression analysis plots are included in Appendix A for comparison.] In the static model, we show that bracelets as signals meaningfully increase individuals' probability to deworm, and that these effects persist when also providing text message reminders and information about others' take-up decisions. Bracelets increase deworming take-up by 8.4 percentage points, a 24 percent increase compared to the control group. We find no detectable effect for the ink incentive, which we attribute to the lower visibility of ink and its strong association with voting in Kenya. Our experiment took place shortly before the presidential election in Kenya, which might have created suspicion among adults. The calendar incentive increased take-up only marginally by 2.7 percentage points. Its effect on take-up is one-third of that of bracelets, despite adults preferring the calendar as consumption item. Building a dynamic model, we explicitly account for potential salience and social learning effects that were introduced as individuals could observe other people's deworming decision. Same as in the static model with the text message treatment, we find no evidence that visibility of actions, through ink or bracelets, affected take-up decisions through reminders or social learning. Lastly, our distance treatment shows that adults are highly sensitive to increases in cost. An increase in the mean walking distance by 1 kilometer leads to a decline in take-up from 44 to 28 percent in the control group. We find that both signals have a larger impact on take-up at far distances, which is consistent with a model of social signaling where returns to signaling increase as signals are more informative about individuals' types. -->
<!-- [^why-bayes]: These are, -->
<!-- (i) The population studied: treatment was stratified over counties and clustered over villages, and household sampling was stratified over phone-ownership. -->
<!-- (ii) The experimental treatments: four village level incentivization/signaling treatment arms, two village level distance assignment arms, and three individual level SMS treatment arms. -->
<!-- Contribution -->
Our work contributes to the literature of social signaling in four ways. First, we provide direct evidence of the effectiveness of making actions observable through a low-cost signal. Recent empirical studies have highlighted the potential negative effects of visibility like in the case of student effort [@Bursztyn2015] and career ambitions [@Bursztyn2017a]. This study shows how social image concerns can be leveraged to increase public goods. Even in the absence of an understanding of externalities, social signals can increase the direct benefits of deworming - as individuals care to be perceived as doing the ``right thing'' - and as a result by acting in their own best interest, they internalize the interests of others (namely reduce the reinfection risk of children whose health is most affected by worms).
Second, this study makes a contribution by exogenously varying distance and with that deworming take-up at the community level. Such is in most settings impossible and allows us to investigate the relationship between equilibrium take-up levels, the informativeness of signals and subsequent differences in the impact of signals on individuals' decision to deworm. By generating large exogenous differences in take-up levels, we show that signals have much larger effects at far distances and can undo the negative demand response observed in the control group. We observe no such effect for the material incentive. This result has the potential to inform policy decisions about optimal treatment locations: as reputational returns are higher at far compared to close distances, increasing individuals' willingness to walk, optimal treatment locations can be set up further apart and with the same number of locations larger geographic areas can be covered.
<!-- Think about this more later in terms of optimal Pigouvian tax, B&T paper; also this claim may need to be substantiated further -->
Third, we show that the type of signal offered can drastically influence its effectiveness. To our knowledge, this is the first study that simultaneously tests two different signals. Our findings suggest that differences in the perceived salience of signals can translate into large differences in their effectiveness to influence behavior. While ink is a known, well-established signal in Kenya - commonly used for voting - our study highlights that such familiarity does not imply it is transferable as signal to another domain.
Fourth, this paper is one of two papers (in addition to @Karing2018) that provides the first evidence on social signaling in health, and therefore contributes to a large literature on incentives to increase the use of health services and public goods in low-income settings [@Thornton2008; @Banerjee2010;@Ashraf2012;@Sato2015]. Complementing Karing's [-@Karing2018] findings, our paper demonstrates the potential effectiveness of social signals in an environment with low take-up levels and where a new technology is introduced.^[In our study, take-up of deworming treatment is 36 percent in the control group, compared to 73 percent take-up of vaccine four in the control groups of Karing's study.]
Lastly, this is one of few studies that directly compares the effect of a material to a social incentive. In line with @Ashraf2012, we show that social signals can outperform a more costly material incentive. Moving beyond existing evidence, our experimental design sheds light on the underlying mechanism and provides convincing evidence for social signaling concerns.
<!-- Clean this up to fit new sections -->
The remainder of this paper is organized as follows. In Section \ref{empirical-setting}, we describe the setting of the intervention. In Section \ref{theoretical-framework}, we present the structural model to describe individual decision-making in the presence of observability of actions. In Section \ref{experimental-design}, we describe the experimental design to identify social signaling concerns. Section \ref{descriptive-statistics}, provides descriptive statistics from the experiment. In Section \ref{empirical-models}, we present the empirical Bayesian model. In Section \ref{results} we discuss the results and section \ref{conclusion} concludes.
# Empirical Setting
Intestinal worms are a development burden to children and adults in many developing countries. According to the World Health Organization approximately 1.5 billion people are infected with soil-transmitted helminths worldwide.^[World Health Organization, Fact Sheet Soil-transmitted helminth infections, September 2017 http://www.who.int/mediacentre/factsheets/fs366/en/.] While mild infections are asymptomatic, more severe infections lead to abdominal pain, iron-deficiency, anemia, malnutrition, and stunting. Epidemiologists postulate that it might be feasible to eliminate worms using mass drug administration covering the entire population, including children and adults. While significant progress has been made in deworming children through school-based deworming programs, the remaining infectious reservoir among adult populations fosters reinfection. An important empirical question is therefore, how high take-up of deworming treatment among adults can be achieved cost-effectively and within a short time.
```{r praise-stigma-plot, fig.width=8, fig.height=3, fig.cap="Reported social perception of some observable activities."}
baseline.data %>%
select(matches("^(praise|stigma)_[^_]+$")) %>%
gather(key = key, value = response) %>%
separate(key, c("praise.stigma", "topic"), "_") %>%
separate(topic, c("topic", "question.group"), -2) %>%
filter(!is.na(response)) %>%
count(praise.stigma, topic, response) %>%
group_by(praise.stigma, topic) %>%
mutate(n = n/sum(n)) %>%
ungroup %>%
mutate_at(vars(praise.stigma, response), ~ fct_relabel(factor(.), str_to_title)) %>%
mutate(topic = fct_recode(factor(topic),
"Wearing/not wearing nice clothes to church" = "clothe",
"Use Latrine/open defecation" = "defecat",
"Deworming/not deworming during MDA" = "dewor",
"Immunize/not immunize children" = "immuniz")) %>%
ggplot(aes(response)) +
geom_col(aes(y = n), alpha = 0.5) +
labs(y = "Proportion", x = "") +
scale_y_continuous(breaks = seq(0.25, 1, 0.25)) +
coord_flip() +
facet_grid(topic ~ praise.stigma, labeller = label_wrap_gen(width = 20)) +
theme_bw() +
theme(legend.position = "bottom",
strip.text.y = element_text(angle = 0),
strip.background = element_rect(colour = NA),
panel.border = element_blank())
```
Community deworming and the context of Western Kenya provide an empirically relevant and suitable setting to study prosocial behavior and the potential of social signaling. Firstly, deworming is a public good. Most of its benefits come through reduced disease transmission to others, while private health benefits are low for many individuals. Secondly, deworming is an established health technology in Kenya. In 2009 the Government of Kenya launched a National School-Based Deworming Programme (NSBDP) through which between 2012 and 2017 over 5 million children got dewormed. Trained teachers administered deworming tablets to all enrolled and non-enrolled children aged 2-14 years in all primary schools in areas endemic to parasitic worms, including our study area. Most likely as a results of that, 78 percent of adults in our baseline survey sample know about deworming treatment and 61 percent are aware that treatment should be taken regularly, every three to twelve months. When asked who is at risk of worm infections, 94 percent of adults answer children and 67 percent answer that adults are at risk too. Only 4 percent say that deworming treatment is for sick people only. Third, there is a strong prescriptive norm around deworming. 95 percent of adults at baseline say they would praise someone who would come for free deworming treatment, while 69 percent said they would look down on a person who did not come. Figure \ref{fig:praise-stigma-plot} shows that image concerns for deworming are comparable to those for open defecation and child immunization. Individuals consider deworming as the "right thing to do" to protect one's health and not spread worms, while those who do not deworm are considered as careless and ignorant. While there could be concerns about adults' interpreting others' decision to deworm as a sign of them having worms or "being dirty" (i.e. revealing negative health characteristic) the baseline data suggests that this is not the case. Instead, deworming is seen as a preventative health behavior for everyone to take, regardless of whether someone believes to have worms or is feeling healthy. However, adults have a limited understanding of externalities. Less than half (41 percent) of adults know that worms can spread between people.^[When asked if a person sick with worms can spread works to others, only 31 percent answered yes, 56 percent said know and 13 percent were uncertain. When asked if "If you have worms, does that affect your neighbors? or relatives? health?" 27 percent and "If your neighbors or relatives have worms, does that affect your health?" 25 percent answered yes. Only 18 percent answered yes to all three questions, had full externality knowledge. 41 percent answered yes to one of the three questions, had partial understanding of externalities.] Lastly, adults under-invest in deworming despite treatment being readily available at a low cost.^[Adults can purchase deworming treatment at pharmacies and clinics for a price of about 50-200 Kenyan shillings (\$0.50-2)] While 68 percent of adults at baseline report to have taken treatment before, only 38 percent say they dewormed in the past 12 month. Adults in endemic areas are advised to deworm every 6 to 12 months but there is currently no formal program that provides free treatment to adults. In collaboration with the Kenyan Government, we implemented a new community deworming program that offered free deworming treatment to over 200,000 adults in Western Kenya. The program was implemented across three counties, Busia, Siaya and Kakamega, where soil-transmitted helminths are endemic. We implemented the program and experiment in two waves: wave one of deworming was implemented from early to mid-October in Busia and Siaya County, and wave two was implemented from late October until early November in Kakamega County. In both waves, deworming started on a Monday and was offered for twelve consecutive days, each day from 8am until 5pm.
# Theoretical Framework
We adapt Bénabou and Tirole's [-@Benabou2006;-@Benabou2012a] framework of prosocial behavior and social signaling to generate predictions and lay out testable assumptions that inform our experimental design. In this framework, individual $i$ decides to take a prosocial action $y \in \{0,1\}$ and values the inference that others will make about her type, based on her observed action:
\begin{align}
U(y;v,x,\lambda) = B(y;v) - C(y) + x\lambda \mathrm{E}_{-i}[v\mid y] \label{equ:signal1}
\end{align}
In our context, $y$ is the decision to deworm or not deworm. Individuals differ in their intrinsic motivation $v$, which is their valuation to contribute to deworming or more generally the community's health. $v$ is drawn from the type distribution $F(v)$ which is assumed to be public knowledge. $v$ is known to individual $i$ but not observable to others. $B(y;v)$ denotes the private benefit of deworming, which is a function of $i$'s choice $y$ and $i$'s type. Deworming treatment is offered for free but adults have to incur a cost $C(y)$ of walking to a treatment location.^[We omit from the model the utility that individuals derive from the externality benefits of deworming. Its inclusion does not affect predictions.]
Ignoring the third term of the model, we have a simple maximization problem where individual $i$ chooses to deworm or not, by maximizing $U_i(y;v) = B(y;v) - C(y)$. Assuming that $B(y;v)$ is increasing and concave, and $C(y)$ is weakly convex, there is a unique function that maps for each individual $i$ her type $v$ to her optimal action: $y^{*} = y(v)$. Without loss of generality, assume that $\frac{\partial B(y;v)}{\partial v} > 0$, such that higher types receive greater utility from deworming.^[Formally $y > y^{'}$ if $v > v^{'}$, $\forall v, v^{'}$.]
The key part of the model is the third term, the reputational benefits and costs associated with the expectations that others will form about $i$'s type as actions become visible. Let $x \in [0,1]$ denote the probability that others observe $i$'s choice. The parameter $\lambda$ measures how much individual $i$ cares about the expectations that others form about her. Following the literature, we assume that $\lambda\geq 0$ given that deworming is socially desirable. In equilibrium, different types choose different actions, leading others to form expectations about $i$'s type conditional on the action observed, that is, $\mathrm{E}_{-i}[v \mid y = 0]$ or $\mathrm{E}_{-i}[v \mid y = 1]$. Importantly, the expectations of others enter directly into $i$'s utility as expressed in equation \ref{equ:signal1}. Following the logic of Bénabou and Tirole [-@Benabou2006;-@Benabou2012a] there exists a unique set of actions under visibility such that each individual chooses an action, given the equilibrium actions of all other individuals. This equilibrium is characterized by the cut-off type $v^*$ (who is indifferent between choosing the optimal $y^{*}=0$ without visibility and deviating to $y^{*}=1$) and the reputational returns which solve the fixed-point equation:
\begin{align}
\underbrace{B(1;v^*) - C(1)}_{\text{Difference in direct benefits}} + \underbrace{x\lambda \Delta[v^*]}_{\text{Net reputational returns }} = 0 \label{equ:signal2}
\end{align}
where^[To make the link between types and actions more transparent, note that $\mathrm{E}_{-i}[v \mid y^{*}=1] - \mathrm{E}_{-i}[v|y^{*}=0] = \mathrm{E}_{-i}[v| v \geq v^*] - \mathrm{E}[v| v < v^*]$.] \[\Delta[v^*]= \underbrace{\mathrm{E}_{-i}[v \mid y^{*} =1] - \mathrm{E}_{-i}[v\mid y^{*} =0]}_{\mathclap{\textrm{Difference in the average type based on \bf{observed} \rm actions}}}.\]
Given our previous assumption $\frac{\partial B(y;v)}{\partial v} > 0$, in equilibrium individuals with higher types will be more likely to take-up deworming treatment than those with lower types.^[It is relatively straight-forward: Suppose, for the sake of contradiction, that there exists an equilibrium in which the action taken by $v, v^{'}$ with $v > v^{'}$ is $y < y^{'}$. By definition the third term concerning other people's inferences, given actions, is the same for all types v. Consequently, if a lower type $v$ prefers to take the action $y^{'}$ instead of $y$, then it must be that a higher type must also prefer the action. That contradicts the initial supposition that they higher type prefers $y$ to $y^{'}$.]
\noindent \bf{Prediction 1.} \rm \it{If it is socially desirable to deworm and individuals care about their reputation (i.e., $\mathrm{E}_{-i}[v\mid y=1] > \mathrm{E}_{-i}[v\mid y=0]$ and $\lambda >0$), deworming take-up will be higher when individuals can signal their participation. The greater the visibility of actions ($x$), the larger the increase in take-up.} \rm \\
\begin{itemize}
\renewcommand\labelitemi{*}
\item \bf{Assumption and mechanism: }\rm \it{Signals increase the visibility of deworming decisions and reduce (perceived) information asymmetries.}\rm \\
\end{itemize}
\noindent The framework further provides insights into how changes in cost affect equilibrium take-up. Following Bénabou and Tirole [-@Benabou2012a], we assume that the type distribution $F(v)$ has finite support $V \equiv [v_{\text{max}},v_{\text{min}} ]$ and a continuously differentiable density $f(v) > 0$. For simplicity, define the equilibrium take-up level of deworming treatment as a function of the cost $c$ as $\bar{y}(c) = 1-F(v^*(c))$, with its derivative $\frac{\mathrm{d} \bar{y}(c)}{\mathrm{d} c} = -f(v^*) \frac{\partial v^*}{\partial c}$. Further, we assume that cost enter individuals' utility function linearly and that the type distribution is unimodal.^[If the type distribution is uniform, reputational returns will be constant, such that a change in $c$ has the same effect on take-up as in the no visibility case.] In the absence of visibility ($x=0$), a one unit increase in $c$ will reduce take-up by $f(v^*)$. As actions become visible (asssume $x=1$), there is an indirect effect ($\sim$ _social multiplier_) of cost on take-up through reputational returns:
\begin{align}
-\frac{\partial v^*}{\partial c} = \frac{-1}{1 + r^{'}(v^*)} \label{eq:social-mult-theory}
\end{align}
where $r^{'}(v^*) = x\lambda\Delta'[v^*]$ is the change in reputational returns, caused by a shift in the cut-off type $v^*$ through the change in cost. Reputational returns change as signals become more or less informative, that is, the difference between $\mathrm{E}_{-i}[v\mid v \geq v^*]$ and $\mathrm{E}_{-i}[v\mid v < v^*]$ increases or decreases:
* If $r^{'}(v^*) <0$ i.e., $\frac{\partial \expect{v|v \geq v^*}}{\partial v^*} < \frac{\partial \expect{v|v <v^*}}{\partial v^*}$ the effect of an increase in cost on take-up will be amplified by a decrease in reputational returns, as signals become less informative. This is the case if take-up of deworming is high ("everyone but the worst people do it") and increases in $c$ lower the pressure on those that do not deworm as the share of non-dewormers increases.
* If $r^{'}(v^*) >0$ i.e., $\frac{\partial \expect{v|v \geq v^*}}{\partial v^*} > \frac{\partial \expect{v|v <v^*}}{\partial v^*}$ the effect of an increase in cost will be mitigated by an increase in reputational returns, as signals become more informative. This is the case if take-up of deworming is low and increases in $c$ increase the praise for those individuals that deworm.^[For there to be a unique equilibrium, we follow @Benabou2012a assuming that $1 + \lambda r^{'}(v_r^{*}) > 0$, which holds for $\lambda$ not too large.]
\noindent \bf{Prediction 2. }\rm \it{Changes in the cost of deworming (by causing changes in the take-up level of deworming treatment) lead to increases (decreases) in reputational returns, increasing (decreasing) the effect of signals and the share of individuals taking up deworming treatment.} \\
\noindent \bf{Alternative Mechanisms.} \rm There are two main confounds to identifying social signaling effects:
1. Signals, in addition to their visibility, might also have a consumption value. Hence, observed changes in deworming take-up might not be due to reputational returns but due to individuals privately valuing the signal.
2. We so far assumed that individuals simultaneously make a decision to deworm and have perfect information about the benefits of deworming. In our experiment, deworming treatment was offered for twelve days.^[The intention was to minimize excuses individuals could make for not taking up treatment and increase the informativeness of signals.] Individuals could therefore observe others' actions before making their own decision and be influenced by:
* _Salience effects:_ As signals increase the salience of others' deworming decisions, individuals might be reminded of deworming.
* _Social learning:_ If adults have inaccurate beliefs about others' deworming take-up, observing others could cause them to update their beliefs about aggregate take-up and the benefits of deworming.
# Experimental Design
<!-- \begin{tikzpicture}[node distance=1cm, auto,] -->
<!-- \node[county] (kakamega) at (-5, -2) {Kakamega County}; -->
<!-- \node[county] (siaya) at (0, -2) {Siaya County}; -->
<!-- \node[county] (busia) at (5, -2) {Busia County}; -->
<!-- \node[punkt] (close) at (-2, -4) {Close} -->
<!-- edge[greypil] (kakamega) -->
<!-- edge[greypil] (busia) -->
<!-- edge[pil] (siaya); -->
<!-- \node[punkt] (far) at (2, -4) {Far} -->
<!-- edge[greypil] (kakamega) -->
<!-- edge[greypil] (busia) -->
<!-- edge[pil] (siaya); -->
<!-- \node[punkt] (control) at (-6, -6) {Control} -->
<!-- edge[pil] (close) -->
<!-- edge[pil] (far); -->
<!-- \node[punkt] (ink) at (-2, -6) {Ink} -->
<!-- edge[pil] (close) -->
<!-- edge[pil] (far); -->
<!-- \node[punkt] (calendar) at (2, -6) {Calendar} -->
<!-- edge[pil] (close) -->
<!-- edge[pil] (far); -->
<!-- \node[punkt] (bracelet) at (6, -6) {Bracelet} -->
<!-- edge[pil] (close) -->
<!-- edge[pil] (far); -->
<!-- \node[triangle, below=of ink] (village1) {} -->
<!-- edge[pil] (ink); -->
<!-- \node[triangle, left=0.25cm of village1] (village2) {} -->
<!-- edge[pil] (ink); -->
<!-- \node[triangle, right=0.75cm of village1] (village3) {} -->
<!-- edge[pil] (ink); -->
<!-- \node[triangle, below=of control] (village1-control) {} -->
<!-- edge[pil] (control); -->
<!-- \node[triangle, left=0.25cm of village1-control] (village2-control) {} -->
<!-- edge[pil] (control); -->
<!-- \node[triangle, right=0.75cm of village1-control] (village3-control) {} -->
<!-- edge[pil] (control); -->
<!-- \node[triangle, below=of calendar] (village1-calendar) {} -->
<!-- edge[pil] (calendar); -->
<!-- \node[triangle, left=0.25cm of village1-calendar] (village2-calendar) {} -->
<!-- edge[pil] (calendar); -->
<!-- \node[triangle, right=0.75cm of village1-calendar] (village3-calendar) {} -->
<!-- edge[pil] (calendar); -->
<!-- \node[triangle, below=of bracelet] (village1-bracelet) {} -->
<!-- edge[pil] (bracelet); -->
<!-- \node[triangle, left=0.25cm of village1-bracelet] (village2-bracelet) {} -->
<!-- edge[pil] (bracelet); -->
<!-- \node[triangle, right=0.75cm of village1-bracelet] (village3-bracelet) {} -->
<!-- edge[pil] (bracelet); -->
<!-- \path (village1) -- node[auto=false,font=\bf]{\ldots} (village3); -->
<!-- \path (village1-control) -- node[auto=false,font=\bf]{\ldots} (village3-control); -->
<!-- \path (village1-calendar) -- node[auto=false,font=\bf]{\ldots} (village3-calendar); -->
<!-- \path (village1-bracelet) -- node[auto=false,font=\bf]{\ldots} (village3-bracelet); -->
<!-- \node[popcircle, below=1.5cm of village2-control, label={below:{\footnotesize\bf{SMS Control}}}] (non-phone-sms-control-control) {} -->
<!-- edge[pil] (village1-control); -->
<!-- \node[popcircle, below=3.5cm of village3-control, label={[text depth=-2ex,text width=4cm,rotate=-35]right:{\footnotesize\bf{SMS Control}}}] (phone-sms-control-control-1) {} -->
<!-- edge[pil] (village1-control); -->
<!-- \node[popcircle, right=0.25cm of phone-sms-control-control-1, label={[text depth=-2ex,text width=4cm,rotate=-35]right:{\footnotesize\bf{Reminders Only}}}] (phone-sms-control-control-2) {} -->
<!-- edge[pil] (village1-control); -->
<!-- \node[popcircle, right=0.25cm of phone-sms-control-control-2, label={[text depth=-2ex,text width=4cm,rotate=-35]right:{\footnotesize\bf{Social Info}}}] (phone-sms-control-control-3) {} -->
<!-- edge[pil] (village1-control); -->
<!-- \node[popcircle, below=1.5cm of village2, label={below:{\footnotesize\bf{SMS Control}}}] (non-phone-sms-control) {} -->
<!-- edge[pil] (village1); -->
<!-- \node[popcircle, below=3.5cm of village3, label={[text depth=-2ex,text width=4cm,rotate=-35]right:{\footnotesize\bf{SMS Control}}}] (phone-sms-control-1) {} -->
<!-- edge[pil] (village1); -->
<!-- \node[popcircle, right=0.25cm of phone-sms-control-1, label={[text depth=-2ex,text width=4cm,rotate=-35]right:{\footnotesize\bf{Social Info}}}] (phone-sms-control-2) {} -->
<!-- edge[pil] (village1); -->
<!-- \begin{pgfonlayer}{background} -->
<!-- \coordinate (strata top right) at (8, -1.1); -->
<!-- \coordinate (strata bottom left) at (-8, -2.9); -->
<!-- \node[expgroup={strata bottom left}{strata top right}, label={[yshift=0.5cm,xshift=6cm]below:{\bf Strata} (Counties)}] (stratabox) {}; -->
<!-- %% \node[rotate=-30, anchor=south] at (stratabox.east) {}; -->
<!-- \coordinate (villages top right) at (8, -7.1); -->
<!-- \coordinate (villages bottom left) at (-8, -8.5); -->
<!-- \node[expgroup={villages bottom left}{villages top right}, label={[yshift=0.5cm, xshift=6cm]below:{\bf Clusters} (Villages)}] (villagesbox) {}; -->
<!-- %%\node[rotate=-30, anchor=south] at (villagesbox.east) {{\bf Clusters}}; -->
<!-- \coordinate (non-phone top right) at (8, -9); -->
<!-- \coordinate (non-phone bottom left) at (-8, -10.52); -->
<!-- \node[expgroup={non-phone bottom left}{non-phone top right}, label={[yshift=0.5cm, xshift=6cm]below:{\bf Non Phone Owners}}] (non-phonebox) {}; -->
<!-- %%\node[rotate=-30, anchor=south] at (non-phonebox.east) {{\bf Non Phone Owners}}; -->
<!-- \coordinate (phone top right) at (8, -11); -->
<!-- \coordinate (phone bottom left) at (-8, -13.3); -->
<!-- \node[expgroup={phone bottom left}{phone top right}, label={[yshift=0.5cm, xshift=6cm]below:{\bf Phone Owners}}] {}; -->
<!-- \end{pgfonlayer} -->
<!-- \end{tikzpicture} -->
\begin{figure}
\centering
\begin{tikzpicture}[node distance=1cm, auto,]
\node[county] (kakamega) at (-5, -2) {Kakamega County};
\node[county] (siaya) at (0, -2) {Siaya County};
\node[county] (busia) at (5, -2) {Busia County};
\node[punkt] (close) at (-2, -4) {Close}
edge[greypil] (kakamega)
edge[greypil] (busia)
edge[pil] (siaya);
\node[punkt] (far) at (2, -4) {Far}
edge[greypil] (kakamega)
edge[greypil] (busia)
edge[pil] (siaya);
\node[punkt] (control) at (-6, -6) {Control}
edge[pil] (close)
edge[pil] (far);
\node[punkt] (ink) at (-2, -6) {Ink}
edge[pil] (close)
edge[pil] (far);
\node[punkt] (calendar) at (2, -6) {Calendar}
edge[pil] (close)
edge[pil] (far);
\node[punkt] (bracelet) at (6, -6) {Bracelet}
edge[pil] (close)
edge[pil] (far);
\node[triangle, below=of ink] (village1) {}
edge[pil] (ink);
\node[triangle, left=0.25cm of village1] (village2) {}
edge[pil] (ink);
\node[triangle, right=0.75cm of village1] (village3) {}
edge[pil] (ink);
\node[triangle, below=of control] (village1-control) {}
edge[pil] (control);
\node[triangle, left=0.25cm of village1-control] (village2-control) {}
edge[pil] (control);
\node[triangle, right=0.75cm of village1-control] (village3-control) {}
edge[pil] (control);
\node[triangle, below=of calendar] (village1-calendar) {}
edge[pil] (calendar);
\node[triangle, left=0.25cm of village1-calendar] (village2-calendar) {}
edge[pil] (calendar);
\node[triangle, right=0.75cm of village1-calendar] (village3-calendar) {}
edge[pil] (calendar);
\node[triangle, below=of bracelet] (village1-bracelet) {}
edge[pil] (bracelet);
\node[triangle, left=0.25cm of village1-bracelet] (village2-bracelet) {}
edge[pil] (bracelet);
\node[triangle, right=0.75cm of village1-bracelet] (village3-bracelet) {}
edge[pil] (bracelet);
\path (village1) -- node[auto=false,font=\bf]{\ldots} (village3);
\path (village1-control) -- node[auto=false,font=\bf]{\ldots} (village3-control);
\path (village1-calendar) -- node[auto=false,font=\bf]{\ldots} (village3-calendar);
\path (village1-bracelet) -- node[auto=false,font=\bf]{\ldots} (village3-bracelet);
\begin{pgfonlayer}{background}
\coordinate (strata top right) at (8, -1.1);
\coordinate (strata bottom left) at (-8, -2.9);
\node[expgroup={strata bottom left}{strata top right}, label={[yshift=0.5cm,xshift=6cm]below:{\bf Strata} (Counties)}] (stratabox) {};
%% \node[rotate=-30, anchor=south] at (stratabox.east) {};
\coordinate (villages top right) at (8, -7.1);
\coordinate (villages bottom left) at (-8, -8.5);
\node[expgroup={villages bottom left}{villages top right}, label={[yshift=0.5cm, xshift=6cm]below:{\bf Clusters} (Villages)}] (villagesbox) {};
%%\node[rotate=-30, anchor=south] at (villagesbox.east) {{\bf Clusters}};
\coordinate (non-phone top right) at (8, -9);
\coordinate (non-phone bottom left) at (-8, -10.52);
%%\node[rotate=-30, anchor=south] at (non-phonebox.east) {{\bf Non Phone Owners}};
\coordinate (phone top right) at (8, -11);
\coordinate (phone bottom left) at (-8, -13.3);
\end{pgfonlayer}
\end{tikzpicture}
\label{fig:exp-design-diagram}
\caption{Experiment Design: grey boxes identity the types of population units over which treatment was assigned. The study was stratified over counties (ellipses) and clustered over villages (triangles). Boxes identify cluster (village) level treatments while circles identify individual level treatments.}
\end{figure}
The first part of this section introduces the different experimental treatments and discusses the identification of signaling preferences. Next, we describe the selection and randomization of treatment points and communities. We then provide an overview of the different data collected and the relevant outcomes.
## Treatments
To create visibility in actions, we experimentally introduce two signals - in the form of a bracelet and ink applied to adults' thumbs. The bracelet and ink create an opportunity for adults to publicly signal that they took deworming treatment. Figure \ref{fig:exp-design-diagram} displays the experimental design which we discuss in the following.
### Social Signals: Ink and Bracelet {-}
```{r bracelet-img, fig.cap="Note: In Swahili it says on the bracelet \"Treat worms improve the health of your community\"."}
knitr::include_graphics(file.path("images", "signal_bracelet.png"))
```
We introduce two different types of signals to increase the visibility of deworming decisions $x$: a green silicone bracelet (Figure \ref{fig:bracelet-img}) and green ink that is applied to a person's thumb. Bracelets and ink were randomized at the cluster level: at 39 treatment locations individuals received a bracelet when coming for deworming and at 36 locations they received ink. The color green was chosen as it is not associated with any political parties and was liked by most individuals during piloting. We test two different signals since it was unclear upfront which one could be more effective.[^signals]
[^signals]: Ink and bracelets vary as signals across important dimensions:
* Ink is known for its use during elections. Individuals get their thumb inked after they cast their vote to avoid double voting. Bracelets are not commonly worn among adults in Kenya.
* Ink has zero or negative consumption utility if individuals perceive it as messy or distrust it due to its link to voting. Bracelets could provide positive consumption value but cannot cause disutility since it is a voluntary signal.
* Bracelets have a high visibility as they are worn around the wrist. Ink's visibility is lower as it is applied to the thumb and only lasts for about 3 days to 2 weeks (on the skin/on the nail).
* The cost of ink is close to zero while a bracelets cost \$0.20. Our research partner, a non-profit, had a strong interest in testing ink.
### Material Incentive: Calendar {-}
```{r calendar-img, fig.cap="Note: The calendar made no reference to deworming to minimize its social signaling value."}
knitr::include_graphics(file.path("images", "calendar.png"))
```
To control for the consumption value $z$ of the bracelet, we introduced a material incentive in the form of a simple one-page wall calendar (Figure \ref{fig:calendar-img}). At 35 treatment locations individuals received the calendar when coming for deworming. The cost of the calendar is 50 Kenyan Shillings (50 Cents). Wall calendars are popular in Kenya as people use them to decorate the walls of their homes and often have many calendars for the same year put up. Due to its durability and visibility inside the home, the calendar would also act as a self-signal to individuals, reminding them of their participation in deworming. 34 treatment locations were randomized into a control arm where no incentives were provided. Signal/incentives were randomized at the cluster level for them to be informative about actions as opposed to adults' preferences for different incentives.
### Cost of Deworming: Close and Far {-}
```{r act-dist, fig.width=8, fig.cap="Distribution of actual distance from targeted villages and their assigned treatment location."}
analysis.data %>%
mutate(assigned.treatment = fct_relabel(assigned.treatment, str_to_title)) %>%
ggplot(aes(dist.to.pot)) +
geom_density(aes(color = dist.pot.group, linetype = "Household")) +
geom_density(aes(color = dist.pot.group, linetype = "Cluster Center"),
data = mutate(village.centers, assigned.treatment = fct_relabel(assigned.treatment, str_to_title))) +
geom_vline(xintercept = c(1250), linetype = "dashed") +
labs(y = "Density",
caption = "Cluster centers were calculated as the centroid location of all households in cluster.") +
scale_x_continuous("Distance to Treatment Location (meters)", breaks = seq(0, 10000, 2500/4)) +
scale_color_discrete("Cluster Distance Assignment", labels = c("Close", "Far")) +
scale_linetype_discrete("Distance From") +
facet_wrap(~ assigned.treatment)
```
```{r dist-to-pot, echo=FALSE, fig.width=6, fig.height=3, fig.cap="Distance to Treatment Locations"}
verify.vill.pot.dist %>%
select(dist.to.own.pot, closest.other) %>%
gather(dist.type, dist) %>% {
ggplot(.) +
geom_histogram(aes(dist, fill = dist.type), binwidth = 2500/4, boundary = 0, alpha = 0.5, color = alpha("black", 0.5), position = "dodge") +
scale_x_continuous("", breaks = seq(0, 10000, 2500/4)) +
scale_y_continuous("Number of Clusters", breaks = seq(0, 100, 5)) +
scale_fill_discrete("Distance", labels = c("To Closest Other Treatment Location", "To Assigned Treatment Location"))
}
```
We vary the cost of deworming and with that the marginal person by varying the distance that individuals have to walk to treatment locations. We randomly assigned communities to either a "close" (0-1.25 kilometers) or "far" (1.25-2. kilometers) deworming location. Due to small changes in the actual location of treatment and the dispersion of households within targeted areas, actual distances to points of treatments were distributed as shown in Figure \ref{fig:act-dist}. While there does appear to be some slight overlap between close and far clusters (i.e. non-compliance with assigned treatment), this does not affect the intention-to-treat analysis. Table 1 shows that individuals from far communities had to travel more than twice the distance to treatment locations compared to individuals from close communities: the randomization shifted the mean distance from 0.84 kilometers to 1.86 kilometers. Figure \ref{fig:dist-to-pot} shows the distribution of targeted communities' distances (in meters) to their own treatment locations and to the closest other treatment locations. The distance to the assigned treatment location was for all clusters, except for two, shorter than the distance to the closest other treatment location.
<!-- ### Reminder and Social Info Text Messages {-} -->
<!-- We introduced a separate treatment at the individual level to hold constant salience and learning effects, and isolate the effect of social signaling. We recruited a random sample of adults in each signal/incentive treatment and the control group to receive text messages with reminders and information about aggregate take-up in their community. The text messages included two statements: "Free deworming now at [Central Location]." (=Reminder) "[No/few/almost half/half/more than half/almost all/all] of your village came, that is X in 10 adults." (=Social Info). We recruited 30 individuals per cluster in the control arm and 25 individuals per cluster in the signal/incentive treatments. In the control arm, we divided the sample into two groups of 15: one group received reminder messages only, and a second group received reminders and social information. In the signal/incentive treatments, individuals always received both. The text message sample was drawn from the population of phone owners, from which we also drew a comparison sample, that did not receive any text messages and also no recruitment visit. The majority of adults (65 percent to 80 percent) in our study sample own a phone. Text messages were sent the day before the deworming program started and after that every other day (on the second, fourth, sixth, eight and tenth deworming day). The first text message, on the day before treatment started, only included the Reminder message in the Social Info treatment since deworming had not yet started. The recruitment for treatment took place one to three weeks before the start of the deworming program. 387 adults were recruited for the reminder treatment in the control group and 2,637 adults across all signal/incentive and control groups for the Social Info treatment. -->
<!-- ### SMS Airtime Reward {-} -->
<!-- To verify that adults were reading the text messages, we offered an airtime reward of 50 Kenyan Shillings (50 US Cents) to a random subset of adults conditional on texting back and confirming the receipt of the text message.^[We only implemented the reward scheme during the second wave of deworming treatment. The reason being, we only decided to add the treatment shortly before we started deworming in wave one communities and had to wait for ethical approval for this added component before we could implement it.] In each control group cluster four adults were randomly selected (two from Reminder and two from Social Info treatment) and in each signal/incentive treatment cluster two adults got selected. The following reward text message was sent to adults on day 2 and 6 of deworming treatment: "Thank you for signing up for this text message from Evidence Action. To receive your 50Ksh airtime reward, message [1234] to [XXX]. The text is free." We sent a reminder text message to adults that had not taken up the reward two days after the original reward text was sent^["Thank you for signing up for text messages from Evidence Action. Don't forget to reclaim your 50Ksh airtime. Message [1234] to [XXX] to receive the reward. The text is free."]. The reminder messages were sent on day 4 (for reward messages sent on day 2) and on day 8 (for reward messages sent on day 6). The SMS airtime reward treatment gives us a lower bound for information take-up for our text message treatment. -->
## Information Campaign Prior to Deworming
```{r sensitization-img, fig.width=8, out.width="5.5in", fig.cap="Note: Community Health Volunteers informed all households in study communities one week prior to the start of the deworming treatment about the social benefits of deworming, when and where free deworming treatment will be available and if applicable what type of incentive will be given to adults when coming for treatment."}
knitr::include_graphics(file.path("images", "sensitization.png"))
```
One week before the launch of the community deworming program Community Health Volunteers (CHVs) together with field researchers visited _each_ of the selected 144 communities to inform adults about the upcoming program.^[Deworming treatment started on a Monday. The information campaign ended on the Friday before the program started to not avoid ``nudging'' adults too close to treatment.] CHVs are trusted community members who are known for their involvement in health campaigns and are part of the school-based deworming program in Kenya. Figure \ref{fig:sensitization-img} shows the information script that CHVs used. The objective was to send a strong message (i) that regular deworming, even in the absence of symptoms, is not only important for children but also for adults and (ii) that deworming is a public good. CHVs further informed community members that ink, calendars and bracelets would be given when coming for deworming, and distributed flyers (see Appendix, Figure 24-26) that displayed the incentives. The objective was to create common knowledge about the meaning of the signals/incentives among community members before the start of the program.
## Site Selection and Randomization
```{r all-clusters-map, message=FALSE, fig.width=6, fig.height=6, fig.cap="Map of Initial Cluster Selection. Black crosses (+) indicate the selected treatment locations, while the grey regions indicate the nonoverlapped catchment circles from which we selected village(s) to target."}
ggplot.clusters(rct.cluster.selection, include.cluster.ids = FALSE, source = "stamen", maptype = "toner")
```
We randomly selected 158 clusters in the three study counties, of which 144 were used in the study.^[We only intended to use 150 clusters, and only included eight extra clusters as fallback clusters. For various practical reasons, implementation was only possible in 144 clusters.] Each cluster was defined as a treatment location and targeted community pair. We used the location of primary schools as proxies to (i) identify acceptable locations to set up our treatment locations and (ii) to find villages to target with our informational campaign and data collection. We relied on the high geographic density of primary schools in the study counties to select both treatment locations and targeted communities.^[Geographic coordinates for primary schools were retrieved from the Kenya Open Data Portal (http://www.opendata.go.ke/).] To select our clusters from the pool of a total of 1,451 primary schools in our study area, we used an acceptance-rejection method whereby we randomly picked schools, checked their acceptability based on their overlap with already selected clusters, and if accepted added them to our selected sample. This process was repeated until we had selected the requisite number of clusters. If no acceptable schools remained before completion, the whole process was restarted. Each cluster, centered on its treatment location, had a 2.5 kilometer radius catchment circle and 3-4 kilometer radius buffer circle. A cluster was considered acceptable if its buffer circle did not leave any of the already selected clusters' non-overlapping catchment circles smaller than an a pre-specified size. Figure \ref{fig:all-clusters-map} shows the final cluster selection. After all clusters were selected, we randomly assigned^[Randomization was stratified within counties.] each cluster to be either a _close_ or _far_ cluster. We then selected for each cluster, from its non-overlapping catchment circle and according to its assigned distance treatment, a primary school as an anchor for us to locate its targeted community.^[For further details on the cluster selection algorithm refer to the study's pre-analysis plan.] Clusters were then randomly assigned, stratified over counties and distance treatment, to the different signal/incentive treatments: control, ink, calendar and bracelet. To finalize the cluster selection process, we surveyed the treatment location and target community anchor schools. For the treatment locations we confirmed that treatment would be feasible there and identified alternative treatment locations, close to the selected schools, as potential backups. For the anchor schools, we identified all the communities near them and randomly selected one community to target.^[In some cases because the initial village was too small, we added a second village.]
## Data and Outcomes
Our analysis uses several data sources, including administrative data on deworming take-up and survey data that was collected before and after the intervention.
(1) _Census data:_ We conducted a census of all adults (18 years age or older) residing in the 144 selected communities: surveyors visited each household, captured their geographic coordinates, and collected basic information of each household member that would allow us to follow-up with individuals and to stratify over relevant characteristics (e.g., phone ownership). In total we listed 38,019 adults. Using the census lists we randomly sampled individuals to be surveyed at base- and/or endline and to be part of the text messaging intervention. The sampling of individuals who did not receive any text messages was stratified over phone ownership.
(2) _Baseline survey data:_ From each of the 144 communities we randomly sampled 15 households and from each household one adult was randomly picked to respond to the baseline survey. We surveyed 4,823 adults about their knowledge about private and social benefits, prior experience and beliefs about deworming take-up and social norms. We reported outcomes under in Section 2. The baseline survey and census were implemented in August and September 2016, eight to five weeks before the start of the deworming program.
(3) _Point of treatment administrative data:_ For all individuals listed in the census, we monitored the decision to take-up deworming treatment directly at the point of treatment. This allowed us to avoid using self-reported data and work with a large sample of 38,019 adults. While CHVs distributed the deworming drugs and incentives, field researchers recorded personal information on electronic devices.
(4) _Endline survey data:_ We surveyed 5,664 adults to verify the correct implementation of all treatments (i.e. information visits by CHVs, receipt and understanding of signals/incentives and text messages), the visibility of signals/incentives, first and second order beliefs and to conduct a separate choice experiment to elicit preferences for calendar and bracelets. The survey was conducted three days to two weeks after the end of the deworming program and the sample included 4,436 respondents that were not part of the text message intervention, and 223 and 1,005 adults who had received the Reminder and Social Info treatment respectively.
Our main outcomes are deworming take-up and beliefs about individual and aggregate level take-up. In our analysis we work with two different samples to estimate the effect of treatments on deworming take-up: i) individuals whose deworming take-up was directly monitored at the point of treatment (N = 12,827) and ii) individuals who were not monitored (N = 25,192). For individuals whose deworming take-up was monitored at the point of treatment personal information was uploaded on tablets so that surveyors could directly verify their attendance. For the larger non-monitored sample of individuals, surveyors manually recorded identifying information at the point of treatment which we matched (through an algorithm) with the census data. We were conservative in the acceptance of names matches, such that deworming levels for the non-monitored sample are significantly lower. When reporting deworming take-up levels we therefore only use data from the smaller, randomly drawn monitored sample. When estimating treatment effects we use the full sample of monitored and non-monitored individuals (N=38,017). In the analysis of beliefs we work with the (base- and) endline survey data.
## Compliance with Implementation Protocol
```{r know-about-mda, message=FALSE, warning=FALSE, fig.width=8, fig.height=6.5, fig.cap="Knowledge of RCT intervention."}
know.mda.cat.plot <- tribble(~ col.name, ~ label,
"know_deworm", "Know about community-based MDA?",
"treat_begin", "Know when MDA starts?",
"treat_end", "Know when MDA ends?",
"days_available", "Know length of MDA?",
"find_out", "From whom or how did you learn about the MDA?",
"chv_visit", "Did a CHV visit you to tell you about MDA?") %>%
multi.know.bel.cat.plot(.baseline.data = NULL, .census.data = NULL) +
scale_y_continuous(breaks = seq(0, 1, 0.1))
day1.wave1 <- as_date("2016-10-03")
day12.wave1 <- day1.wave1 + days(11)
day1.wave2 <- as_date("2016-10-24")
day12.wave2 <- day1.wave2 + days(11)
wave.dates <- tribble(~ wave, ~ begin.end, ~ day,
1, "begin", day1.wave1,
1, "end", day12.wave1,
2, "begin", day1.wave2,
2, "end", day12.wave2)
mda.dates.dist.plot <- endline.data %>%
select(wave, treat_begin, treat_end, treat_begin_date, treat_end_date) %>%
gather(key = begin.end, value = day, -c(treat_begin, treat_end, wave)) %>%
mutate(begin.end = if_else(begin.end == "treat_begin_date", "begin", "end")) %>%
filter((treat_begin == "knows" & begin.end == "begin") | (treat_end == "knows" & begin.end == "end")) %>%
ggplot(aes(day)) +
geom_histogram(aes(fill = begin.end), alpha = 0.75, binwidth = 2, position = "identity") +
geom_vline(aes(xintercept = as.numeric(day)), linetype = "dotted", data = wave.dates) +
# scale_x_date(breaks = c(day1.wave1, day12.wave1, day1.wave2, day12.wave2)) +
scale_x_date("", date_breaks = "4 weeks", date_minor_breaks = "1 week", limits = c(as_date("2016-09-05"), as_date("2016-11-28"))) +
scale_y_continuous("") +
scale_fill_discrete("", labels = c("Begin Date", "End Date")) +
facet_wrap(~ wave, scales = "free_x", labeller = as_labeller(. %>% sprintf("Wave %s", .))) +
labs(title = "When did the MDA begin and end?", caption = "Dotted vertical lines identify correct MDA start and end days.") +
theme(legend.position = "right")
grid.arrange(know.mda.cat.plot, mda.dates.dist.plot, layout_matrix = as.matrix(c(1, 1, 1, 2, 2)))
```
Figure \ref{fig:know-about-mda} shows how well adults were informed about the deworming program. At endline (2-14 days after the end of treatment), 89 percent of individuals knew that deworming treatment was offered to adults in their community. 74 percent reported to have received an information visit from a CHV before the start of the program. 69 percent of adults were able to recall the number of days that treatment was offered. Almost all individuals that came for deworming treatment, reported that they had received the assigned signal/incentive at the point of treatment (95 percent for ink, 97 percent for bracelet and 95 percent for calendar). All adults who were recruited for the text message treatment, consented to receiving the messages (confirm this, some did not have phone?). 82 percent of endline respondents that had been assigned to the text message treatment reported to have received messages. When asked about the content of the messages, 98 percent said that the message was a reminder for deworming and 47 percent said that the messages told them about how many people had dewormed. The average number of reported messages received was 4, with 75 percent of people reporting to have received between 3 and 6 text messages. It is possible that individuals do not precisely recall the number of messages received, given that the endline survey took place 2-14 days after deworming treatment had ended.
# Descriptive Statistics
In this section we will present descriptive statistics pertinent to implementation of the community deworming program and its outcomes.
### Study sample {-}
Table \ref{tab:cluster-stats} shows the total number of clusters by treatment arm and county as well as the number of adults that were surveyed during the census. Across 144 cluster, we surveyed 39,301 individuals who formed the sampling frame for different surveys and text messaging intervention.
<!-- useless sentence and should definitely move table to appendix later. useful only if we describe different sample, where this is super sample and then there is monitored, monitored consent and endline sample -->
```{r cluster-stats}
cluster.stats <- census.data %>%
filter(!is.na(cluster.id)) %>%
left_join(select(cluster.strat.data, cluster.id, dist.pot.group), "cluster.id") %>%
arrange(county)
calc.cluster.stats <- . %>%
count(county, assigned.treatment) %>%
ungroup %>%
spread(assigned.treatment, n) %>% {
total <- select(., -county) %>% mutate_all(as.integer) %>% rowSums
mutate(., all = total)
}
clusters.stats <- cluster.stats %>%
distinct(cluster.id, .keep_all = TRUE) %>%
calc.cluster.stats %>%
set_names(str_to_title(names(.)))
individ.stats <- cluster.stats %>%
calc.cluster.stats %>%
set_names(str_to_title(names(.)))
```
\begin{table}
\centering
\caption{Number of clusters and individuals in targeted communities, by county and treatment arm.}\label{tab:cluster-stats}
\begin{tabular}{l*{10}{c}}
\toprule
& \multicolumn{5}{c}{Clusters} & \multicolumn{5}{c}{Individuals} \\ \\
County & Control & Ink & Calendar & Bracelet & All & Control & Ink & Calendar & Bracelet & All \\
\cmidrule(r){2-6} \cmidrule(r){7-11}
```{r cluster-stats-tab, results="asis"}
clusters.stats %>%
left_join(individ.stats, "County", suffix = c(".clusters", ".individuals")) %>%
plyr::a_ply(1, function(row) sprintf("%s %s \\\\\n",
row$County,
paste(sprintf(" & %s", prettyNum(as.integer(row[, -1]), big.mark = ",")), collapse = "")) %>%
cat)
```
\bottomrule
\end{tabular}
\end{table}
Figure \ref{fig:general-desc-stats} shows socio-economic characteristics of individuals in the census, base- and endline survey. The mean age is 35 and 40 years respectively. Over half of respondents have not completed primary education and a large share (80$\%$) live in houses with floors made of earth. Both is indicative of low-income status, yet 65$\%$ to 80$\%$ of respondents report to have a mobile phone across the different surveys.
```{r general-desc-stats, fig.width=8, fig.height=6, warning=FALSE, fig.cap="Study population summary statistics"}
gen.stats.plot <- tribble(~ col.name, ~ label,
"gender", "Gender",
"ethnicity2", "Ethnicity",
"school", "Schooling",
"floor", "Home floor construction",
"have_phone", "Own mobile phone?") %>%
multi.know.bel.cat.plot(.census.data = census.data %>% mutate(gender = factor(gender, levels = 1:2, labels = c("Male", "Female"))),
preprocess.fun = . %>% mutate(response = fct_relevel(response, rev(levels(baseline.data$school)))),
na.rm = TRUE)
age.density.plot <- list(Census = mutate(census.data, age = age.census),
Baseline = baseline.data,
Endline = endline.data) %>%
map_df(~ select(., age), .id = "survey.type") %>%
mutate(survey.type = factor(survey.type, levels = c("Census", "Baseline", "Endline"))) %>%
ggplot(aes(survey.type, age, color = survey.type)) +
geom_boxplot() +
coord_flip() +
scale_y_continuous("Age Box Plot", breaks = seq(15, 100, 5)) +
labs(x = "") +
theme(legend.position = "none")
grid.arrange(gen.stats.plot, age.density.plot, layout_matrix = as.matrix(c(1, 1, 1, 1, 2)))
```
<!--Gender decomposition -->
### Knowledge, beliefs and perceptions of deworming {-}
Figure \ref{fig:know-believe-categorical-responses} presents individuals' responses to base- and endline questions about worms and deworming treatment. The majority of respondents knew about deworming treatment (78$\%$). However, less than one third of adults had knowledge of the negative externalities of worm infection. Comparing reported knowledge and beliefs of baseline and endline surveyed individuals, the most significant change is in people's understanding of who is at risk of worm infections. More people are reporting after the intervention the belief that everyone is at risk of worm infection.
<!-- TOOK OUT since people are both less likely to answer yes and no to this question, as if they were less open to answering the question after deworming took place "Surprisingly, there seems to be a decrease in the understanding that individuals can infection one another. -->
```{r know-believe-categorical-responses, warning=FALSE, fig.width=8, fig.height=10, fig.cap="Knowledge and beliefs baseline and endline survey responses."}
tribble(~ col.name, ~ label,
"who_worms", "Who is at risk of worms?",
"effect_worms", "What are the effects of worms?",
"spread_worms", "Can an infected person spread worms to other?",
"how_spread", "How are worms spread?",
"stop_worms", "How to stop worms?",
"when_treat", "When should people get dewormed?",
"worms_affect", "If infected, can you affect others' health?",
"neighbours_worms_affect", "Can neighbors or relatives worm infection affect your health?") %>%
multi.know.bel.cat.plot() +
scale_y_continuous(breaks = seq(0, 1, 0.1))
```
Since our study's main research questions focus on social influence in deworming decisions, we tried to elicit individuals' perceptions and beliefs of others' deworming choices. Figure \ref{fig:response-other-deworm} shows individuals reporting that their own deworming decisions would not be influenced by others' decisions, as well as having a strong _intention_ to getting dewormed.
```{r response-other-deworm, warning=FALSE, fig.width=8, fig.height=2.5, fig.cap="Reported response to others' deworming choices."}
tribble(~ col.name, ~ label,
"few_deworm", "Deworm if less than half of others deworm?",
"many_deworm", "Deworm if more than half of others deworm?",
"more_less", "Would you be more likely to deworm if few/many others get dewormed?") %>%
multi.know.bel.cat.plot(.endline.data = NULL) +
scale_y_continuous(breaks = seq(0, 1, 0.1))
```
In addition, as shown in Figure \ref{fig:baseline-deworming-beliefs}, people predicted similar deworming among peers. As we will see below, most people overestimated their own and others' deworming take-up. Finally, when individuals were asked about how others would respond to the use of indelible ink as a signal of deworming treatment, they predicted a positive effect, contrary to what we actually observed.
```{r survey-of-10-beliefs, ref.label="survey-of-10-beliefs", warning=FALSE}
```
```{r survey-of-10-beliefs-boxplot, ref.label="survey-of-10-beliefs-boxplot", warning=FALSE}
```
```{r baseline-deworming-beliefs, warning=FALSE, fig.width=8, fig.height=5, fig.cap="Baseline beliefs/predictions about others' deworming choices."}
other.predict.deworm.plot <- tribble(~ col.name, ~ label,
"dworm_proportion", "How many people will come to get dewormed?",
"ink_more_less", "Will the ink signal increase/decrease deworming take-up?") %>%
multi.know.bel.cat.plot(.endline.data = NULL,
preprocess.fun = . %>%
mutate(response = fct_relevel(response,
"Few", "Nearly Half", "Half", "More Than Half", "Many", "All", "Less", "Same", "More", "Prefer Not Say", "Don't Know"))) +
scale_y_continuous(breaks = seq(0, 1, 0.1)) +
labs(title = "Peer deworming predictions")
survey.takeup.beliefs.10 <- list(Baseline = baseline.data, Endline = endline.data) %>%
compact %>%
map_df(select, one_of("dworm_rate", "ink_dworm_rate"), .id = "survey.type") %>%
gather(key = incentive, value = value, -survey.type) %>%
mutate(incentive = if_else(incentive == "dworm_rate", "None", "Ink")) %>%
ggplot(aes(value)) +
geom_freqpoly(aes(y = ..density.., color = survey.type, linetype = incentive), binwidth = 1) +
scale_x_continuous("Reported Rate", breaks = 0:10) +
scale_y_continuous("Density") +
scale_color_discrete("") +
scale_linetype_manual("Signal", values = c("dashed", "solid")) +
theme(legend.position = "bottom") +
labs(title = "How many out of 10 will come for deworming?")
survey.takeup.beliefs.10.boxplot <- list(Baseline = baseline.data, Endline = endline.data) %>%
compact %>%
map_df(select, one_of("dworm_rate", "ink_dworm_rate"), .id = "survey.type") %>%
gather(key = incentive, value = value, -survey.type) %>%
mutate(incentive = if_else(incentive == "dworm_rate", "None", "Ink")) %>%
ggplot(aes(survey.type)) +
geom_boxplot(aes(y = value, color = survey.type, linetype = incentive), position = position_dodge(width = 1.1)) +
scale_y_continuous("Reported Rate", breaks = 0:10) +
scale_color_discrete("") +
scale_x_discrete("") +
coord_flip() +
scale_linetype_manual("Signal", values = c("dotdash", "solid")) +
theme(legend.position = "bottom", axis.text.y = element_blank(), axis.ticks.y = element_blank())
survey.takeup.beliefs.10.boxplot <- survey.takeup.beliefs.10.boxplot + theme(legend.position = "none")
survey.takeup.beliefs.10 <- survey.takeup.beliefs.10 + theme(legend.position = "right")