Water Quality Case Study: Kenya Rural Water Project

Water Quality Case Study: Kenya Rural Water Project

Michael Kremer, Harvard University and NBEREdward Miguel, U.C. Berkeley and NBER

Jessica Leino, World BankSendhil Mullainathan, Harvard University and NBER

Clair Null, Emory UniversityAlix Zwane, Bill and Melinda Gates Foundation

Presented by Vivian Hoffmann, University of Maryland

DIME-AADAPT SARDecember 19, 2009

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Motivation

• 2 million children die of diarrheal diseases annually, contaminated water is important pathway of transmission

• Domestic water is a common demand in CDD initiatives (especially by women)

• Impact evaluations can help identify effective technologies for improving water quality

• Same methodologies can also help identify which technologies are valued by beneficiaries

• Essential to understand willingness-to-pay for scale-up and long-run sustainability

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Setting• Rural Western Kenya

• Demographics– Mothers have 6 years of education– 4 children under age 12; 1 or 2 children under age 3 per

compound

• Water– Nearest source is 8 minute walk from compound– Most households get water from unprotected springs– < 20% of HH’s meet US drinking water standard– < 30% boiled yesterday’s drinking water

• Hygiene & Sanitation– > 80% have a pit latrine– > 90% have a soap

4October 2008 - CAS Trickle Down 4

5October 2008 - CAS Trickle Down 5

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The Project (Phase I)• Multiple interventions to improve water quality

• Researchers worked with a local NGO

• 652 springs were identified for protection to improve water quality and convenience

• Due to capacity constraints, able to protect only one quarter of total springs each year

• Randomized order of phase-in

• Compared with household water treatment intervention (chlorine)

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Household Water Treatment

• Point-of-use treatment with dilute chlorine reduces diarrheal disease by around 40%, yet relatively few households use chlorine even in areas exposed to several years of vigorous social marketing

• In 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

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• 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

• 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

Identify Springs

Protect in years 1-2 Protect in years 2-4

randomize

Baseline HH survey, water quality tests,

GPS data

Interventions

Follow-up HH survey & water quality tests

randomize randomize

6 mo chlorine + coupons

control

6 mo chlorine + persuasion

6 mo chlorine

Study Design (Phase I)Spring Protection vs. Chlorine Distribution

control

6 mo chlorine + coupons

6 mo chlorine + persuasion

6 mo chlorine

Data

• Distance to main source of drinking water (GPS)

• Water quality (fecal coliform) at the spring

• Water quality in the home

• Residual of chlorine in drinking water – for study households and social contacts

• Coupon redemption – from shopkeepers

• Child diarrhea – reported by mother

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Summary of Spring Protection Results

• Protecting springs led to 66% less source contamination, moderate gains at home; child diarrhea fell by a 25%

• Households value spring protection at 12.7 work days ($4.52-$9.02) per year

• Policy implications: comparing this to the cost of spring protection, it appears socially optimal to only protect springs with large numbers of household users. (does not include health benefits)

Household Water Quality Impacts

Child Health Impacts

Price and WaterGuard Use0

2040

6080

100

% o

f Hou

seho

lds

with

chlo

rinat

ed d

rinki

ng w

ater

Price=0(Household visit)

Price=10(Coupons)

Price=20(Social marketing)

Self-reported Positive test Coupon redemption

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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

• Present study found no evidence that households who stand to benefit most from cleaner water (i.e. those with young children) have higher willingness to pay

• Draws into question appropriateness of retail model

Sample of Springs

Study Design (Phase II)Alternative Approaches to Promoting HH Chlorine Use

randomize

Flat fee promoter + coupon for

one free bottle

Social Marketing

Control Chlorine dispenser + incentive pay

promoter

Incentive pay

promoter + coupon for one free bottle

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Point-of-collection Chlorine Dispenser

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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

Take-up by Treatment Arm0

2040

6080

100

% o

f Hou

seho

lds

with

chlo

rinat

ed d

rinki

ng w

ater

Compa

rison

H.H. S

cript

Comm. S

cript

H.H. +

Com

m. Scri

pt

F.F. Pro

m. + C

pn.

Incen

. Prom

. + C

pn.

Incen

. Prom

. + D

isp.

Short-run (~3 weeks):Self-reportPositive test

Medium-run (3-6 months):Self-reportPositive test

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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

Take-up of Free Chlorine0

2040

6080

100

% o

f Hou

seho

lds

with

chlo

rinat

ed d

rinki

ng w

ater

Indiv. Bottles +HH visit

Dispenser +Promoter

(Baseline HH's)

Dispenser +Promoter

(Non-Baseline HH's)

Self-report Positive test

Conclusions: Household Water Treatment• 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

• 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)

Lessons for Impact Evaluation

• Possible to learn a lot by trying multiple strategies– varied technology, price, message

• Iterative design allows development of effective new approaches– e.g. free delivery works (but is expensive) chlorine

dispenser makes free delivery much cheaper– next step: how to manage and finance dispensers?

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Thank you!