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Field
Abstract
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Before
At least 2 billion people around the world drink water from a contaminated source. About two million children die every year from diarrheal diseases and around 700 million people worldwide are affected by chronic kidney disease because of unsafe drinking water and sanitation, despite the availability of effective and inexpensive technologies to improve water quality (Null et al. 2012). Most efforts to provide clean water focused on the technology of chlorine (adding chlorine or chlorine compounds such as sodium hypochlorite to water), which is affordable and easy to use (see, for example, Amrita, Kremer, and Zwane 2010; Null et al. 2012; Dupas et al. 2022).
Despite the evidence of health benefits associated with chlorine water, empirical evidence indicates that most households in developing countries are not willing to adopt and pay much for it (Amrita, Kremer, and Zwane 2010; Null et al. 2012; Berry, Fischer, and Guiteras 2020). Indeed, Dupas et al. (2016) and Dupas et al. (2022) report that less than half of households consume chlorine water even when they receive chlorine for free.
A plausible hypothesis is that previous efforts to promote adoption of clean water disregard the importance of understanding the local culture. Our hypothesis is that there are factors explaining the low take-up rates (and willingness to pay) of chlorine water other than price itself or lack of adequate information. In particular, we propose that dislike for taste of chlorinated water and/or its cultural unsuitability might explain low adoption rates (and willingness to pay). Moreover, in rural areas with high illiteracy rates, people may use taste as a strong signal of healthy water more than standard information messages. To test this hypoyhesis, we will run two separate experiments with women residing in rural village in Upper Egypt. We focus on medium to large sized villages with poor water quality, high incidence of water-borne diseases (such as diarrhea and kidney failures), and without NGOs providing water related services in the area.
The first experiment consists of a blind test between chlorinated and filtered water or tea. While health status is equalized between the two samples of water, they differ in taste. While health and taste is equalized between filtered water and tea, they differ in cultural relevance since consumption of tea is strongly embedded in local habits and social traditions. After tasting water (or tea), women will report which water they prefer, as well as express health perceptions on both samples of water.
In the second experiment, we propose a randomized design at the household level in two rural villages in Upper Egypt. In our experiment, there are 3 groups: a treatment group, a control group, and a pure control group. The treatment group will be offered a tank of 10 liters of healthy filtered water. The control group will be offered a tank of 10 liters of chlorine water. Finally, the pure control group will not be offered cleaned water. Both treated and control women will taste water (or tea) from the offered tank before proceeding to express their adoption decision and willingness-to-pay (WTP). In a follow-up visit, we will measure the effect of the intervention on health and hygiene measures, as well as domestic violence, in the treatment and pure control group.
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After
At least 2 billion people around the world drink water from a contaminated source. About two million children die every year from diarrheal diseases and around 700 million people worldwide are affected by chronic kidney disease because of unsafe drinking water and sanitation, despite the availability of effective and inexpensive technologies to improve water quality (Null et al. 2012). Most efforts to provide clean water focused on the technology of chlorine (adding chlorine or chlorine compounds such as sodium hypochlorite to water), which is affordable and easy to use (see, for example, Amrita, Kremer, and Zwane 2010; Null et al. 2012; Dupas et al. 2022).
Despite the evidence of health benefits associated with chlorinated water, empirical evidence indicates that most households in developing countries are not willing to adopt and pay much for it (Amrita, Kremer, and Zwane 2010; Null et al. 2012; Berry, Fischer, and Guiteras 2020). Indeed, Dupas et al. (2016) and Dupas et al. (2022) report that less than half of households consume chlorinated water even when they receive chlorine for free.
A plausible hypothesis is that previous efforts to promote adoption of clean water disregard the importance of understanding the local culture, namely local taste and tradition. Our hypothesis is that dislike for taste of chlorinated water and/or its cultural unsuitability might explain the low take-up rates (and willingness to pay) of chlorinated water, other than price itself or lack of adequate information. Moreover, in rural areas with high illiteracy rates, people may use taste as a strong signal of healthy water more than standard information messages.
Specifically, we provide experimental evidence that local taste and traditions are important –yet overlooked so far– dimensions in the decision of adopting clean water. We introduce a new culturally-friendly technology that produces clean water taking into account local culture and preferences, by filtering local water in water treatment units. Differently from chlorination, this technology does not alter the taste of water, nor the taste of traditional beverages that are a relevant part of locals’ consumption habits and sociality. Moreover, in rural areas with high illiteracy rates, people may use taste as a strong signal of healthy water.
We study this question in rural Egypt, where groundwater sources exhibit increasing levels of contamination and salinity due to seawater intrusion and soil degradation (Said et al., 2021). We perform four different experiments using samples of filtered and chlorinated water. While the two types of water are healthier than status-quo water, they differ in taste, since filtered water is closer to the taste individuals expect in local water and traditional beverages. The first experiment consists of a blind test where respondents test both a sample of filtered and chlorinated water, not knowing the types of water, and then indicate their preferred sample. Second, we test if filtered water leads to higher adoption rates and willingness-to-pay for clean water using the Becker et al. (1964) mechanism. The third experiment explores underlying reasons behind the preferences revealed in the previous experiments by investgating individuals' perceptions of taste, health and cultural suitability of filtered and chlorinated water. Lastly, we inspect long-run health and socio-economic outcomes following adoption of treated and chlorinated water.
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Trial Start Date
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Before
October 01, 2022
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After
May 29, 2023
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Trial End Date
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Before
May 31, 2023
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After
December 31, 2023
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Last Published
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Before
August 29, 2022 05:20 PM
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After
May 11, 2023 02:23 PM
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Intervention (Public)
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Before
First Experiment
The first experiment consists of a blind test between chlorine water and filtered water. While health status is equalized between the two samples of water, they differ in taste. Half of the sample would be offered chlorinated and filtered water, while the other half would receive chlorinated and filtered tea. Tasting of the water will happen in private, so respondents cannot influence each other answers. Also, we will randomize the order at the time one person enters into the experiment place, with 50% chance of tasting filtered water (or tea) first and other 50% chance of tasting chlorinated water (or tea) first. After tasting the water, we will record which water (or tea) they prefer. Our hypothesis is that individuals will prefer filtered water/tea. Moreover, following the blind taste, we will ask respondents to rank, on a scale from 1 to 10, their perception of healthiness of the two waters/teas.
Second Experiment
We propose a randomized design at the household level in two rural villages in Upper Egypt. The respondent of all surveys (pre-treatment and follow-up) will be the woman in charge of the household, who is typically the one that fetch water. We focus on medium to large sized villages with poor water quality, high incidence of water-borne diseases (such as diarrhea and kidney failures), and without NGOs providing water related services in the area.
In our experiment, there are 3 groups: a treatment group, a control group, and a pure control group. We will organize two home visits: pre-treatment visit, and a follow-up visit after 2 months.
In the pre-treatment visit, we include the treatment and the control group. The treatment group will be offered a tank of 10 liters of healthy filtered water. The control group will be offered a tank of 10 liters of chlorine water. Finally, the pure control group will not be offered cleaned water and will not be visited in this round. Both treated and control women will taste water (or tea) from the offered tank before proceeding to express their adoption decision and willingness-to-pay (WTP).
To study individuals’ choices in a real-life scenario, in our experiment we will focus on a setting where water tanks are delivered home by home by water taxis going to fetch water to the local treatment unit. The range of prices in the willingness-to-pay experiment includes prices that reflect both the cost of the tank and the cost of transportation.
After the first home visit, before leaving the house, treated people will receive a free voucher for the water taxis to obtain filtered water home for 2 months. Relevantly, both the control and pure control won’t be served by the water taxis for this period of time.
The follow-up visit will take place after 2 months, and we will survey only the treated and pure control group. In this round, we will record long-term outcomes related to health, women's outcomes and household dynamics.
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After
First Experiment: Blind Test
The first experiment explores whether individuals prefer chlorinated water or filtered water. This experiment consists of a “blind test” between samples of chlorinated water and filtered water. Eligible population includes men and women aged 18 or more who are permanent residents of the villages. Each individual tests both a samples of filtered and chlorinated water, not knowing the types of water, and then indicates the preferred sample. Since, in Egypt, tea is an everyday beverage drank during meals, shared in social gatherings, and as an alternative to water during the day, the taste of tea made with clean water could affect people’s decision to adopt. We explore for this by randomly assigning half of the individuals in the blind test to taste plain water (both filtered and chlorinated) and the other half to taste tea (both made with filtered and chlorinated water). To avoid potential biases, we randomly assign the order in which individuals taste the samples.
Second Experiment: Willingess-to-Pay
In the second experiment we measure willingness to pay. This experiment focuses on women, who are typically the ones in charge of fetching water. We randomly assign half women to the treatment group (filtered water) and half to the control group (chlorinated water). After trying a sample of the water (all women try both plain water and tea), the woman states her willingness to pay for a 20-liter bucket of water. To obtain women’s willingness-to-pay, the woman first states an offer price for the 20 liters of water. Then a random transaction price is drawn (in our context choosing one envelope from an unmarked set). If the random transaction price is greater than the offer price, the woman cannot purchase the product. If the random price is less than or equal to the offer price, she has to purchase the product, and pays the random transaction price draw rather than the stated offer. For expected utility maximizers, the optimal strategy is to bid the true maximum willingness to pay (Becker, Degroot, and Marschak 1964).
Third experiment: Mechanisms
The third experiment explores underlying reasons behind the preferences revealed in the first experiment. However, filtered water is both healthier and tastier than chlorinated water, so the reasons for filtered water being preferred are not yet known. For this third experiment, we produce a new water that is as healthy as filtered water, but that taste as the local chlorinated water. That is, the two waters are equally healthy but differ in taste. Individuals are randomly assigned to taste either filtered (treatment) or chlorinated water (control) and, after tasting, are asked to describe the water in terms of its taste, health and cultural suitability (i.e. suitability to prepare traditional food and beverages). This allows us to identify the dimension(s) in which filtered water is superior to chlorinated water. On top of that, before tasting the water, we inform all participants that the water they will taste is healthy. In this way, we equalize actual information on health. Therefore, remaining differences in health perceptions can be attributed only to taste, which is the only signal about the quality of water that the individual receives after the disclosure of information.
Fourth Experiment: Health
In the fourth experiment, we randomly assign households to 3 groups: a treatment group, a control group, and a pure control group. The treatment group will receive a free voucher to obtain filtered water delivered at home for 2 months. The control group will receive a free voucher to obtain chlorinated water delivered at home for 2 months. Finally, the pure control group will not be offered any clean water. A follow-up visit will take place after 2 months, and we will survey household both in the treated and in the control group in order to record medium-term outcomes. In the medium term, there is a direct link between consumption of dirty water and diseases such as diarrhea and kidney problems. In addition, fetching clean water is time-and-labor-intensive, which could detract from education or productive activities, a burden that falls disproportionately on women and children. Lastly, since women are responsible for domestic water management (e.g., cleaning dishes, doing laundry, preparing food), they are usually blamed by their husbands for water-related issues, increasing the chances of intimate partner violence. That is, we will study the medium-term effect of clean-water adoption on water-related diseases, women’s working decisions, children’s education, and intimate partner violence.
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Intervention Start Date
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Before
October 01, 2022
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After
May 29, 2023
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Intervention End Date
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Before
May 31, 2023
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After
December 31, 2023
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Primary Outcomes (End Points)
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Before
Preference for chlorinated and filtered water (or tea); health perceptions; willingness-to-pay and adoption of filtered and chlorinated water; health (water-borne illnesses); women's outcomes (e.g. savings, etc.); domestic violence.
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After
Preference for chlorinated and filtered water (or tea); health, taste and tradition perceptions; willingness-to-pay and adoption of filtered and chlorinated water; health (water-borne illnesses); women's outcomes (e.g. savings, etc.); domestic violence.
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Primary Outcomes (Explanation)
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Before
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After
A) Preference for chlorinated and filtered water (or tea)
- Which sample did you prefer?
(Enumerator indicates the cups and understand which water sample the respondent preferred. 1 = Chlorinated; 2 = Filtered; 3 = Both; 4 = Neither)
B) Health, taste and tradition perceptions
- On a scale from 1 to 5, how much do you think this water/tea is tasty, where 1 is very bad tasting and 5 is extremely tasty?
- On a scale from 1 to 5, how much do you think this water/tea is healthy, where 1 is extremely unhealthy and 5 is extremely health?
- On a scale from 1 to 5, how much do you think the color of this water/tea looks good, where 1 is "looks extremely bad" and 5 is "looks extremely good"?
- On a scale from 1 to 5, how much do you think this water/tea is suitable to prepare your traditional drinks (e.g. tea) and cook your traditional dishes, where 1 is extremely unsuitable and 5 is extremely suitable?
C) Willingness-to-pay and adoption
Becker, Degroot, and Marschak (1964) procedure
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Experimental Design (Public)
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Before
We propose a randomized design at the household level in two rural villages in Upper Egypt. The respondent of all surveys (pre-treatment and follow-up) will be the woman in charge of the household, who is typically the one that fetch water.
In our experiment, there are 3 groups: a treatment group, a control group, and a pure control group. We will organize two home visits: pre-treatment visit, and a follow-up visit after 2 months.
In the pre-treatment visit, we include the treatment and the control group. The treatment group will be offered a tank of 10 liters of healthy filtered water. The control group will be offered a tank of 10 liters of chlorine water. Finally, the pure control group will not be offered cleaned water and will not be visited in this round.
The follow-up visit will take place after 2 months, and we will survey only the treated and pure control group. In this round, we will record long-term outcomes.
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After
First experiment (blind test), second experiment (willingness-to-pay) and third experiment (mechanisms): The first three experiments are conducted in the same 8 villages in rural Upper Egypt. We propose a randomized design at the individual level, stratified by village. We recruit different individuals for each experiment. In the first and third experiment, we recruit individuals in the village aged 18 or more. In the second experiment, the respondent will be the woman in charge of the household, who is typically the one that fetches water.
In the first experiment, we randomly assign half of the sample to taste both filtered and chlorinated water (n=100), and the other half to taste both filtered and chlorinated tea (n=100). Additionally, to avoid potential biases related to the order of testing the samples, within each treatment arm, half of the individuals are randomly assigned to taste chlorinated water first and the other half to taste filtered water first.
In the second experiment, half of the sample (n=200) is randomly assigned to the treatment group (taste filtered water and elicit willingess-to-pay) and half (n=200) to the control group (taste chlorinated water and elicit willingess-to-pay).
In the third experiment, half of the sample (n=100) is randomly assigned to taste filtered water (treated group) and half (n=100) chlorinated water (control group). In each of the three experiments, we will administer the treatment followed by the related survey measures.
Fourth experiment (health): It is conducted in the same 8 villages in rural Upper Egypt. We propose a randomized design at the household level, stratified by village. We randomly assign househols to 3 groups: a treatment group (n=700), a control group (n=700), and a pure control group (n=700). We conduct a survey after 2 months from the intervention.
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Randomization Method
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Before
Randomization done in office by a computer
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After
First experiment (blind test), second experiment (willingness-to-pay) and third experiment (mechanisms): randomization done on the spot with device
Fourth experiment (health): randomization done by a computer
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Randomization Unit
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Before
Random assignment will be at the household level. Our experimental design stratifies at the surveyor level.
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After
First experiment (blind test), second experiment (willingness-to-pay) and third experiment (mechanisms): Random assignment will be at the individual level. Our experimental design stratifies at the village level.
Fourth experiment (health): Random assignment will be at the household level. Our experimental design stratifies at the village level.
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Planned Number of Observations
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Before
First experiment: 400 individuals
Second experiment: 2100 women
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After
First experiment (blind test): 200 individuals
Second experiment (willingness-to-pay): 400 women
Third experiment (mechanisms): 200 individuals
Fourth experiment (health): 2100 households
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Sample size (or number of clusters) by treatment arms
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Before
700 women treatment (filtered water), 700 women control (chlorinated water), 700 women pure control
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After
First experiment (blind test): 100 individuals (filtered and chlorinated water), 100 individuals (filtered and chlorinated tea)
Second experiment (willingness-to-pay): 200 women (filtered water), 200 women (chlorinated water)
Third experiment (mechanisms): 100 individuals (filtered water), 100 individuals (chlorinated water)
Fourth experiment (health): 700 households (filtered water), 700 households (chlorinated water), 700 households (pure control)
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Power calculation: Minimum Detectable Effect Size for Main Outcomes
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Before
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After
Exploratory analysis from a small-scale pilot experiment in Upper Egypt suggest that most individuals prefer filtered water to chlorinated water (90% of the sample) and adoption rates are 30 percentage points higher for filtered water than chlorinated water. Power calculations suggest a sample of 400 could detect a MDE of 8 percentage point for the primary outcome.
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Did you obtain IRB approval for this study?
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Before
No
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After
Yes
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