Trickle Down: Chlorine Dispensers and Household Water Treatment Michael Kremer, Harvard University and NBER Edward Miguel, U.C. Berkeley and NBER Sendhil Mullainathan, Harvard University and NBER Clair Null, U.C. Berkeley Alix Zwane, google.org Perspectives on Impact Evaluation March 31, 2009

Perspectives on Impact Evaluation 2 Motivation Adoption of new technologies is often surprisingly slow in less-developed countries Impact evaluations can help identify useful technologies Same methodologies can also help identify which technologies are valued by constituents Essential to understand willingness-to-pay for scale-up and long-run sustainability Important in context of larger debate about cost-sharing for goods and services subsidized by development agencies –Demand effects –Supply effects

March 31, 2009Perspectives on Impact Evaluation 3 Household Water Treatment 2 million children die of diarrhea annually Point-of-use treatment with dilute chlorine could drastically cut this toll, yet relatively few households use chlorine even in areas exposed to several years of vigorous social marketing In our Kenyan study area: –70-90% of households familiar with local brand of chlorine –About as many volunteer that “dirty” water is a cause of diarrhea –Only 5-10% of households regularly use chlorine to treat their water

March 31, 2009Perspectives on Impact Evaluation 444 Dilute chlorine (similar to chlorination in centralized water supplies in rich countries) Safe: developed by US. CDC & PAHO, distributed and marketed by Population Services International in over 20 countries Chlorine smell and taste is strong at first (prevents overdosing / kids drinking straight from bottle), fades after a few hours One capful disinfects 20L of water, with residual protection against recontamination Wait 30 minutes after treatment before water consumed 150 mL bottle treats a household’s water supply for roughly one month Costs 20 KSh (US$0.30), a quarter of the daily agricultural wage

March 31, 2009Perspectives on Impact Evaluation 55 How to increase take-up? Use series of randomized evaluations to understand factors affecting take-up: –Price –Persuasion –Peer effects –Product’s delivery system Iterative research process –Use results from first phase to design strategies that increase take-up –Then test alternative strategies –Future work will focus on how to make most effective strategies sustainable and scalable

March 31, 2009Perspectives on Impact Evaluation 666 Setting Demographics –Mothers have 6 years of education –4 children under age 12; 1 or 2 children under age 3 Water –Nearest source is 8 minute walk from compound –< 20% of HH’s meet E.P.A. drinking water standard –< 30% boiled yesterday’s drinking water Hygiene & Sanitation –> 80% have a pit latrine –> 90% have a soap

March 31, 2009Perspectives on Impact Evaluation 77 Phase 1: WaterGuard Intervention All treatment households received: –7 bottles of WaterGuard –Voucher for improved clay storage pot with tap and lid Enumerators engaged subjects in a “directed conversation” about water contamination and prevention strategies –Explained dosing procedures –Answered subjects’ questions 1/3 of treatment households were also given a wall calendar and 12 coupons (redeemable monthly) for 50% discount on WaterGuard at local shops 1/3 of treatment households chosen for intensive persuasion campaign

March 31, 2009Perspectives on Impact Evaluation 8 Study Design Part of larger on-going Rural Water Project –Spring protection as source water quality improvement 184 communities; 7-8 households sampled at each Half of sampled HH’s randomly chosen for intervention –Community-level randomization to generate exogenous variation in exposure to WaterGuard through social networks “High intensity” intervention: 6 households out of 8 chosen “Low intensity” intervention: 2 households out of 8 chosen Intervention conducted after 3 rd household survey Follow-up survey 2-7 months later Coupon data collected from shop-keepers

Price and WaterGuard Use

March 31, 2009Perspectives on Impact Evaluation 10 Can price serve as a screening mechanism? Some argue that price will help to screen out those who aren’t likely to value or use the product –Ashraf, Berry, and Shapiro (2008) in peri-urban Zambia We find no evidence that households who stand to benefit most from cleaner water (i.e. those with young children) have higher willingness to pay –Understanding the link between water and health might be more important Draws into question appropriateness of retail model

March 31, 2009Perspectives on Impact Evaluation 11 Persuasion and Peers More intensive marketing messages had no effect on take-up Rich relationship data on all pair-wise combinations of sampled households in each spring community Intervention drastically increased frequency of conversations about WaterGuard Mixed evidence of take-up effects depending on outcome –On basis of self-reported chlorine, comparison household twice as likely to use chlorine if all of her close friends were members of treatment group (sig. at 90% confidence) –On basis of positive chlorine tests, no effect of social networks Members of the same tribe and community leaders are especially influential on the basis of either measure

March 31, 2009Perspectives on Impact Evaluation 12 Phase 2: Alternative Strategies to Promote Take-up Group 0 – Pure comparison Group 1 – Persuasive scripts: Group 1A – Household script only Group 1B – Community script only Group 1C – Household + community scripts Group 2 – Promoters + coupon for 1 free bottle / household: Group 2A – Flat-fee promoter Group 2B – Incentivized promoter (paid per positive test) Group 3 – Promoters + dispenser

March 31, 2009Perspectives on Impact Evaluation 13 Point-of-collection Chlorine Dispenser

March 31, 2009Perspectives on Impact Evaluation 14 Point-of-collection Chlorine Dispenser Drastically cuts the cost of supplying chlorine –Approximately 25% of current individually-packaged retail cost Salience Convenience –Walk home provides agitation and some of wait time –Dose is more precise; doesn’t get on hands Habit formation –Links water treatment to existing habits associated with water collection Harnesses social network effects –Makes decision public

March 31, 2009Perspectives on Impact Evaluation 15 Study Design 88 springs randomized into community-level interventions Household-level script randomization at comparison & community script springs Baseline surveys, interventions –~20 sampled household’s per spring Short-run follow-up (~3 weeks) –increase sample by ~5 household’s per spring Medium-run follow-up (3-6 months)

Take-up by Treatment Arm

Take-up of Free Chlorine

Conclusions Very high take-up rates of chlorine for point-of-use water treatment when it is provided for free –But demand is very sensitive to price Persuasive messages don’t seem to make much difference beyond short-run; mixed evidence on peer effects, but community leaders do seem important Local chlorine promoters were very influential, even when price discounts ran out –Combine potential of persuasive messages and peer effects Changing the way the product is delivered could be the solution: Point-of-collection chlorine dispensers hold the most promise for a sustainable strategy for increasing take-up at scale –Drastically reduces cost (mainly through packaging) –Harnesses peer effects by making use decision public –Helps to build habits of consistent use (more convenient)

March 31, 2009Perspectives on Impact Evaluation 19 Thank you!