Promoting water purification: The roles of learning, habit formation, and social norm

Last registered on January 30, 2019

Pre-Trial

Trial Information

General Information

Title
Promoting water purification: The roles of learning, habit formation, and social norm
RCT ID
AEARCTR-0003673
Initial registration date
December 14, 2018
Last updated
January 30, 2019, 6:26 AM EST

Locations

Region

Primary Investigator

Affiliation
Lahore University of Management Sciences

Other Primary Investigator(s)

PI Affiliation
IDinsight
PI Affiliation
Harvard Business School
PI Affiliation
World Bank

Additional Trial Information

Status
In development
Start date
2019-03-15
End date
2020-12-30
Secondary IDs
Abstract
Despite the potential to reduce diarrheal disease burden (Quick, et al, 2002), use of affordable point-of-use decontamination technologies such as chlorine tablets is low in many developing countries including Pakistan (0.3%, with 8% adopting any purification technology; Pakistan DHS, 2012-13). While price - even when low - can hinder adoption, free access induces only partial usage. For example, free delivery of chlorine solution in Kenya yielded a usage rate of only 34% (Dupas, et al, 2016). However, there is little evidence on ways to increase usage beyond this basic level induced by access. Akram & Mendelsohn (2017; hereafter, AM) explore an alternative hypothesis: If the households do not understand - or trust - expert opinion on benefits of usage and benefits are hard to measure, they may not be convinced of the returns to such a technology. In a pilot RCT, AM use household recordkeeping of children’s diarrhea incidence to help them learn the benefits of chlorinated drinking water (along with sharing information on the diarrhea rate from a comparable population not exposed to chlorine). Compared to a base policy of free access to chlorine tablets and expert advice on why to use them, this simple intervention increased chlorine use after one year by a remarkable 56 percentage points. It was highly cost-effective as well, with the marginal cost per DALY-averted at $495. We propose to build on this pilot by a) testing at a larger scale and b) investigating mechanisms, particularly those related to learning and social norms, to inform design choices for the next stage(s) of experimentation and eventually scale-up. The experimental design is further structured to test learning against habit formation: both processes require intense initial engagement and can yield sustained behavioral change, but economists know little about which is most effective for behavioral change (and technology adoption) broadly. Particularly in a space where returns are not obvious and existing information campaigns have largely failed, investigating which mental process is most operative regarding long term adoption of preventive health behaviors is crucial to policy design: do we, as policymakers, invest in subsidizing an activity repeatedly so people develop a habit, or do we invest in improving our information campaigns so individuals can better understand the returns to a behavior?
External Link(s)

Registration Citation

Citation
Akram, Agha et al. 2019. "Promoting water purification: The roles of learning, habit formation, and social norm." AEA RCT Registry. January 30. https://doi.org/10.1257/rct.3673-3.0
Former Citation
Akram, Agha et al. 2019. "Promoting water purification: The roles of learning, habit formation, and social norm." AEA RCT Registry. January 30. https://www.socialscienceregistry.org/trials/3673/history/40858
Experimental Details

Interventions

Intervention(s)
Our interventions comprise the following broad components:

Monitoring: Biweekly health worker (hereafter, HW) visits to - a) collect data on diarrhea incidence over the last two weeks, b) test chlorine in the water, and c) offer free chlorine tablets (2-week’s supply) along with expert advice on use. These mimic standard public health campaigns around chlorine distribution.

Info-tool: HW helps the caregiver record diarrheal incidence (unique episodes across children) and total diarrhea days (the sum of all diarrhea days across episodes and children) and creates a bar graph to visually represent the total diarrhea days experienced by the children in the household in the last two weeks. At the end of each month (i.e. during the second biweekly visit in a month), the diarrhea days from that month are added up and colored into a month-level bar graph;

Social Norm: HW shares information on the monthly diarrhea days expected in households that do not use chlorine (to be estimated using data directly from the experiment); and

Habit formation with financial incentive: Caregivers are offered rewards (tokens redeemable for child or household goods) if water tested positive for chlorine; size of incentive to be calibrated to match the short-run take up of tablets in T1 (see experimental design below).
Intervention Start Date
2019-04-01
Intervention End Date
2020-03-31

Primary Outcomes

Primary Outcomes (end points)
Presence of residual chlorine in household drinking water; Acceptance of offered chlorine tablets; Diarrhea prevalence
Primary Outcomes (explanation)

Secondary Outcomes

Secondary Outcomes (end points)
Height-for-age Z-score; Weight-for-height Z-score
Secondary Outcomes (explanation)
Z-scores will be constructed using the WHO child growth standards (WHO 2007).

Experimental Design

Experimental Design
Our interventions or experimental arms comprise the following broad components:

Monitoring: Biweekly health worker (hereafter, HW) visits to - a) collect data on diarrhea incidence over the last two weeks, b) test chlorine in the water, and c) offer free chlorine tablets (2-week’s supply) along with expert advice on use. These mimic standard public health campaigns around chlorine distribution.

Info-tool: HW helps the caregiver record diarrheal incidence (unique episodes across children) and total diarrhea days (the sum of all diarrhea days across episodes and children) and creates a bar graph to visually represent the total diarrhea days experienced by the children in the household in the last two weeks. At the end of each month (i.e. during the second biweekly visit in a month), the diarrhea days from that month are added up and colored into a month-level bar graph;

Social Norm: HW shares information on the monthly diarrhea days expected in households that do not use chlorine (to be estimated using data directly from the experiment); and

Habit formation with financial incentive: Caregivers are offered rewards (tokens redeemable for child or household goods) if water tested positive for chlorine; size of incentive to be calibrated to match the short-run take up of tablets in T1.

Using combinations of the above, we propose the following four experimental arms:

Comparison (C): Monitoring
Treatment 1 (T1): Monitoring + Info-tool
Treatment 2 (T2): Monitoring + Info-tool + Social Norm
Treatment 3 (T3): Monitoring + Habit formation with financial incentive
Experimental Design Details
Randomization Method
Randomization done in office
Randomization Unit
Household (with at least one under-five child)
Was the treatment clustered?
No

Experiment Characteristics

Sample size: planned number of clusters
1,400 Households
Sample size: planned number of observations
1,400 Households
Sample size (or number of clusters) by treatment arms
350 Households
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
1. Presence of residual chlorine in household drinking water (proportion; MDE: 11 pp) 2. Acceptance of offered chlorine tablets (proportion; MDE: 11 pp) 3. Number of days a child under five had diarrhea (days; MDE: 0.176)
IRB

Institutional Review Boards (IRBs)

IRB Name
IRB Approval Date
IRB Approval Number

Post-Trial

Post Trial Information

Study Withdrawal

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Intervention

Is the intervention completed?
No
Data Collection Complete
Data Publication

Data Publication

Is public data available?
No

Program Files

Program Files
Reports, Papers & Other Materials

Relevant Paper(s)

Reports & Other Materials