Stormwater Management and Climate Change Adaptation Impact Evaluation 2014-2016

A first challenge in data collection resulted from the fluid nature of urban communities in the study area. As mentioned in Section IV (OQP Intervention), quartiers and CBOs are sometimes dynamic units. At the time of the baseline survey, a small subset of pre-identified quartiers (4) and CBOs (16), identified earlier in the study design process, could not be located. Missing quartiers and CBOs were replaced. This issue did not reemerge during the follow-up, suggesting that the “missing” quartiers and CBOs were anomalies. While it is perhaps not so unusual for CBOs to disband, the disappearance of a geographic unit such as a quartier warrants further attention. It should be noted, however, that the list of quartiers was created by PROGEP’s SFs, and so the four missing quartiers are likely due to errors in that process.

A second challenge related to locating households and CBOs for the follow-up (or endline) survey. The household and CBO surveys are both panel surveys, which means that the same households and CBOs were surveyed at baseline and follow-up. While identifying CBOs at follow-up was relatively straightforward – particularly for those in the treatment group – identifying households in the baseline sample was more complicated given the absence of a formal system of street names and addresses.

At baseline, GPS coordinates for each household were taken in addition to other identifying information. These coordinates were to be the primary means of re-identifying households. These data, however, turned out to be of little use due to the density of the cities of Pikine and Guédiawaye and the lack of precision in GPS measurement (e.g. a precision of 100 meters can include the totality of houses in one quartier). To overcome this challenge, enumerators relied on neighbor networks and baseline “addresses” to locate the correct households. If a household could not be initially located, the enumerator followed a replacement protocol. These measures allowed us to achieve a low attrition rate: out of the 2,400 households surveyed at baseline, only 115 could not be included in the endline survey, an attrition rate of less than 5%. Table 6 of the survey report summarizes the target and achieved sample sizes for the household and CBO surveys at baseline and endline.