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Impact Evaluation on the Distribution of Plastic Latrine Slabs and Improving Households Sanitation in Rural Kenya
Last registered on February 18, 2020


Trial Information
General Information
Impact Evaluation on the Distribution of Plastic Latrine Slabs and Improving Households Sanitation in Rural Kenya
Initial registration date
April 07, 2017
Last updated
February 18, 2020 10:05 AM EST
Primary Investigator
Other Primary Investigator(s)
PI Affiliation
Water Practice, World Bank, Washington DC
PI Affiliation
World Bank, Nairobi, Kenya
PI Affiliation
Kenya Medical Research Institute, Nairobi, Kenya
PI Affiliation
World Bank, Nairobi, Kenya
PI Affiliation
Ministry of Health, Nairobi, Kenya
Additional Trial Information
Start date
End date
Secondary IDs
Over two-thirds of Kenyans lack access to improved sanitation, a significant public health burden that costs the country nearly one percent of its GDP every year. In order to support acceleration of access to improved sanitation in Kenya, the World Bank is working directly with large plastics manufacturing firms, grassroots and local MFIs, local retailers, and the government to design, test, and support market development and distribution strategies for a range of plastic latrine slabs.

The objective of this impact evaluation is to learn whether niche distribution and financing mechanisms are effective for reaching the base-of-the-pyramid and to evaluate health impact and cost-effectiveness of plastic latrine slabs. This study is being conducted in Busia and Nyeri counties of Kenya, where the Water and Sanitation Program of the World Bank is implementing the Selling Sanitation initiative jointly with International Finance Corporation. A key outcome of the study will be to inform future strategies of reaching households at the base of the pyramid with improved sanitation products.
External Link(s)
Registration Citation
Chase, Claire et al. 2020. "Impact Evaluation on the Distribution of Plastic Latrine Slabs and Improving Households Sanitation in Rural Kenya." AEA RCT Registry. February 18. https://doi.org/10.1257/rct.2133-2.0.
Former Citation
Chase, Claire et al. 2020. "Impact Evaluation on the Distribution of Plastic Latrine Slabs and Improving Households Sanitation in Rural Kenya." AEA RCT Registry. February 18. http://www.socialscienceregistry.org/trials/2133/history/62944.
Experimental Details
Intervention Start Date
Intervention End Date
Primary Outcomes
Primary Outcomes (end points)
- Coverage (uptake) of plastic latrine slabs
- Willingness-to-pay of plastic latrine slabs
- Health outcomes: diarrheal prevalence and weight-for-age z-scores (WAZ) for children under five
Primary Outcomes (explanation)
Secondary Outcomes
Secondary Outcomes (end points)
Secondary Outcomes (explanation)
Experimental Design
Experimental Design
The impact evaluation uses an experimental approach, consisting of a three-arm cluster randomized controlled trial (RCT) with random assignment at village/cluster level. The three arms are as follows:
1. Distribution and financing arm: Grassroots savings and investment groups offer direct sales and financing to consumers, to examine market penetration and sales of plastic slabs.
2. Health arm: Households are provided with plastic slabs to test the efficacy of the slabs on health outcomes.
3. Control arm: Manufacturers of the plastic slabs are free to distribute through existing channels, but without support for setting up these new channels of distribution.
Experimental Design Details
Randomization Method
Computer generated
Randomization Unit
Was the treatment clustered?
Experiment Characteristics
Sample size: planned number of clusters
Sample size: planned number of observations
3915 households
Sample size (or number of clusters) by treatment arms
1. Distribution and financing arm: 450 households in 30 villages
2. Health arm: 1540 households in 77 villages
3. Control arm: 1925 households in 77 villages
Minimum detectable effect size for main outcomes (accounting for sample design and clustering)
IRB Name
AMREF Ethics and Scientific Review Committee
IRB Approval Date
IRB Approval Number
AMREF-ESRC P155/2014
Post Trial Information
Study Withdrawal
Is the intervention completed?
Intervention Completion Date
August 01, 2015, 12:00 AM +00:00
Is data collection complete?
Data Collection Completion Date
April 30, 2017, 12:00 AM +00:00
Final Sample Size: Number of Clusters (Unit of Randomization)
Was attrition correlated with treatment status?
Final Sample Size: Total Number of Observations
Final Sample Size (or Number of Clusters) by Treatment Arms
Data Publication
Data Publication
Is public data available?
Program Files
Program Files
Reports, Papers & Other Materials
Relevant Paper(s)
Improving access to safe and affordable sanitation facilities is a global health priority that is essential for meeting the United Nation’s Sustainable Development Goals. To promote the use of improved sanitation in rural and low-income settings, plastic latrine slabs provide a simple option for upgrading traditional pit latrines. The International Finance Corporation/World Bank Selling Sanitation program estimated that plastic slabs would have a 34% annual growth, with a market size of US$2.53 million in Kenya by 2017. In this study, we examined the commercial viability of these plastic latrine slabs in rural Kenya by evaluating a financing and distribution model intervention, documenting household slab sales to date, and assessing consumer exposure and perceptions. We also determined household willingness to pay through a real-money auction with 322 households. We found that no households in our study area had purchased the plastic slabs. The primary barriers to slab sales were limited marketing activities and low demand compared with the sales price: households were willing to pay an average of US$5 compared with a market price of US$16. Therefore, current household demand for the plastic latrine slabs in rural Kenya is too low to support commercial distribution. Further efforts are required to align the price of plastic latrine slabs with consumer demand in this setting, such as additional demand creation, product financing, and public sector investment.
1. Peletz, R., Kisiangani, J., Ronoh, P., Cock-Esteb, A., Chase, C., Khush, R., Luoto, J. (2019). Assessing the Demand for Plastic Latrine Slabs in Rural Kenya. The American Journal of Tropical Medicine and Hygiene. 101(3), 2019, pp. 555–565, doi:10.4269/ajtmh.18-0888