Trickle Down: Diffusion of Chlorine for Drinking Water Treatment in Kenya. Michael Kremer, Harvard University and NBER Edward Miguel, U.C. Berkeley and NBER Clair Null, U.C. Berkeley Alix Zwane, google.org. The Economics of Rural Water. Source water improvements vs point-of-use (POU)
Michael Kremer, Harvard University and NBER
Edward Miguel, U.C. Berkeley and NBER
Clair Null, U.C. Berkeley
Alix Zwane, google.org
Source water improvements vs point-of-use (POU)
Source water improvements serve many households simultaneously, thus require cooperation; POU is private decision by HH
Possibility of recontamination during storage & transport
Randomized evaluation of alternative water interventions in rural western Kenya
Source water quality improvement
Point-of-use water treatment (chlorination)
Increased water quantity
Alternative institutions for community maintenance of water sources
This paper: we study distribution of 6-month supply of free sodium hypochlorite (WaterGuard) to a subset of households in 184 rural Kenyan communities
Child mortality in Kenya is high at 120 per 1000 live births (2005), and even higher in rural areas
Diarrheal disease is a leading cause
Lack of knowledge about diarrhea & POU’s doesn’t seem to be a major problem:
72% of study households volunteer that “dirty water” is a cause of diarrhea
87% of study households have previously heard of WaterGuard
But take-up is low: only 3% of study households have chlorine in water prior to intervention
1) What are the impacts of free chlorine distribution on:
-- Home water quality?
-- Child health?
-- Household behaviors?
2) What is the relationship between clean water & diarrhea?
3) How does information about chlorine spread through a community?
-- Is there a “tipping point” for network effects?
-- What sorts of relationships are relevant?
-- What types of people are influential?
4) How does the distribution of free chlorine affect social networks & conversation patterns in the community?
Baseline survey (Aug 2004 – Feb 2005)
47 of 184 springs protected
Follow-up survey #1 (Apr – Aug 2005)
Pre-intervention social network data collected
93 of 184 springs protected
Follow-up survey #2 (Aug – Nov 2006)
WaterGuard intervention conducted
Follow-up survey #3 (Jan – Mar 2007)
Post-intervention social network data collected
Tested for levels of fecal indicator bacteria E. coli at spring and in home (all 4 survey rounds)
Tested for residual chlorine in home water (last 2 survey rounds)
Water collection (source choice, number of trips, walking distance) and water-related behaviors
Hygiene knowledge, sanitation
Child health (diarrhea), anthropometrics
Household demographic, socioeconomic variables
Social networks data
all pair-wise combinations of study households within spring community
frequency of conversations about children’s health problems, drinking water, & chlorine
Diarrhea prevalence of 20% among kids 3 or younger in control households
Pre-intervention difference in diarrhea between treatment & control children of 4 percentage points (22% versus 18%, respectively; significant at 95%)
Treatment associated with ~8 percentage point reduction in diarrhea on average (significant at 95%)
No differential treatment effects for boys versus girls or on the basis of other household characteristics (latrines, hygiene knowledge, mother’s education, etc.)
Why is take-up so low / high?
Who isn’t using it?
Can we say anything about why they don’t use it? (externalities?)
What is the binding constraint to reducing diarrhea?
Chlorine doesn’t kill everything
What will happen in the long(er)-run? Adoption of free chlorine versus adoption of purchased chlorine