Market-based sanitation reduces diarrheal disease in rural Cambodia

iDE believes that market-based approaches, which encourage households to invest in aspirational products, will drive latrine uptake and proper usage more than giving away products for free. While iDE tracks sales to ensure that our business-approach is working, the real goal for sanitation marketing is the increased use of latrines by households. We survey users on a regular basis to measure usage rates; since these surveys rely on self-reporting by the respondents, they are potentially subject to bias. 97% of customers report adults (18 years of age or older) using the latrine always or almost always. That number drops to 93% when asked about children, with 6% of the households reporting children use the latrine only sometimes. We can see the area for greatest improvement is with infant feces disposal as only 21% dispose of infant feces in the latrine always or almost always. Over half (51%) of customers report never or almost never disposing of infant feces in the latrine.

We also tested differences in reported use among poverty status and provinces. There were no significant differences in use rates across IDPoor status or province, except in the case of use in Oddar Meanchey. Whereas all other provinces saw self-reported adult use range between 97-99%, in Oddar Meanchey the adult report use is only 75%. This depressed trend holds consistent across children and infant use rates. It will be important to understand what is responsible for this provincial outlier for future behavior messaging in that province.

Another aspect of iDE’s sanitation marketing is the indirect messaging that promotes the use of latrines over open defecation. Knowledge about good sanitation practices learned by households from group and one-on-one presentations can help drive this change, even if the household can’t afford their own toilet. For example, we’ve seen increased instances of latrine sharing. The table below presents the proportion of households sharing a latrine among non-latrine owners and within the larger population. Among households that do not own a latrine, the percent of those sharing a latrine with another household has increased from 8% in our 2014 survey to 23% during the last survey in 2018. This suggests that in addition to improved latrine coverage rates increasing, more households are also gaining access to a latrine via sharing. This could indicate more households entering the sanitation ladder and are positioned for latrine ownership.

Reduction in diarrheal disease

With increased usage comes the real impact: the reduction in diarrheal disease across households. A recent study from Georgetown University examined primary data iDE collected in annual latrine count surveys in conjunction with secondary data from the Cambodia Socio-Economic Survey (CSES) and the USAID-funded Demographic Health Survey (DHS) in order to answer the following research questions about the first phase of iDE’s sanitation marketing intervention:

1. Did iDE’s intervention lead to increases in latrine coverage?
2. Did iDE’s intervention lead to improvements in health?

In particular, this study estimated the causal attribution of iDE’s intervention on these two outcomes of interest. While our internal data collections have tracked the change in coverage over time, this study provides an externally conducted evaluation of our causal impact.

The researchers found that iDE’s sanitation marketing increased the latrine coverage rate by 105% in iDE’s intervention area as compared to the control area, after controlling for commune characteristics. They also found that sanitation marketing led to decreases in diarrhea prevalence by 6.5 percentage points in the intervention area compared to the control area, after controlling for district characteristics.

For more information: Sanitation Marketing Improving Health Outcomes