I think all evaluation questions require a mixed approach. Data collection tools are just tools; they should be used opportunistically -- when it works -- but definitely not idolized. That would be like a plumber who loves wrenches but doesn't like screwdrivers, and who tries to do everything with a wrench, including screwing in screws... That would be absurd: a good plumber uses several tools, when and as necessary, and doesn't ask himself what type of plumbing requires only one tool...
Likewise, a good evaluator needs to know how to use a toolbox, with several tools in it, not just a wrench.
I agree with Vincente that qualitative work must always PRECEDE a quantitative effort. Before measuring something, you need to know why and how to measure it, and for that you need a QUALITATIVE understanding of the object of measurement. One of the most common mistakes made by "randomistas" is precisely that they spend a lot of time and money on surveys that are too long and complex, because they don't know what's important to measure. So they try to measure everything with endless questionnaires, and regularly fail.
RE: How are mixed methods used in programme evaluation?
Hello Jean, and thank you for your question!
I think all evaluation questions require a mixed approach. Data collection tools are just tools; they should be used opportunistically -- when it works -- but definitely not idolized. That would be like a plumber who loves wrenches but doesn't like screwdrivers, and who tries to do everything with a wrench, including screwing in screws... That would be absurd: a good plumber uses several tools, when and as necessary, and doesn't ask himself what type of plumbing requires only one tool...
Likewise, a good evaluator needs to know how to use a toolbox, with several tools in it, not just a wrench.
I agree with Vincente that qualitative work must always PRECEDE a quantitative effort. Before measuring something, you need to know why and how to measure it, and for that you need a QUALITATIVE understanding of the object of measurement. One of the most common mistakes made by "randomistas" is precisely that they spend a lot of time and money on surveys that are too long and complex, because they don't know what's important to measure. So they try to measure everything with endless questionnaires, and regularly fail.
[Translated from French]