Posted by: ebtosun | October 1, 2010

Improving Water Systems with an Unlikely Science

As a student in an international development program, our own development work in Waslala comes to mind in almost every class I take.  In Institutions, we’re discussing how community norms can be included in policy designs.  In Sparking Social Change, we’re talking about the benefits from inciting communities to drive their own change.  Even in Microeconomics, we’re seeing how targeted social programs can be designed to reach their intended recipients.

However, the subject matter I am studying this semester that is perhaps the most relevant to WfW is… Statistics.  What?  Statistics??  How can something so– let’s be honest– dry and boring be relevant to our development work?  Actually, statistical analysis is an essential tool to determine the impact of our work in Waslala.

About a year ago, I worked with Meaghan Gruber, our Project Manager in Waslala, to design a set of survey questions for our beneficiaries before and after the systems were built.  These questions would provide a framework to quantify how much time would be saved from installing potable water systems and how much healthier families would become as a result of the system installations.

Now (I’ll try to make this as free of statistical jargon as possible!) I want to underscore a key point about impact evaluation.  In the ideal statistical impact study, we would choose a random group of people to receive a “treatment” (in our case, a water system) and compare this treatment group to another random group of people who did not receive a water system (the “control”).

In Waslala, we can’t do this. Precisely because of point #2 in Nora Pillard’s most recent post, we need to involve the community in site selection, so our selection of people receiving the treatment cannot be random.  However, what we can do is at least collect some meaningful data from families before and after the system is installed in order to make a qualitative comparison.

Though we may not be able to quantify our impact in as rigorous statistical terms as we would like, I am looking forward to conducting the follow-up survey with the beneficiaries of our newest system, El Varillal, next spring so that we can learn from our first “impact” results.  I’m also looking forward to working with the new Project Manager in Waslala to continually refine our survey questions in order to gain a clearer and clearer understanding of the true impact from our work.

Elise Tosun is a student in the Masters in Public Administration/International Development (MPA/ID) program at the Harvard Kennedy School.  She will graduate in 2012.



  1. […] my last post, I covered the basics of Impact Evaluation 101 (the need for a “treatment” and […]

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