To cluster or not to cluster? Not to cluster…

Jonathan Lain Methodology, Real Geek

Getting standard errors right is important for anyone trying to do quantitative impact evaluation. We want to know that any impacts of the project that we observe are real, rather than just the result of random variation in the data. In this blog post, Jonathan Lain focuses on one particular aspect of calculating standard errors that has proved a real …

Rising to the challenge: Measuring an expanding concept of resilience in Oxfam’s impact evaluations

Jonathan Lain Methodology, Real Geek

Resilience has become central to the development sector in recent years, but conceptually it is still in a state of flux. In this blog post, we explore some of the new challenges associated with measuring the expanding concept of resilience in Oxfam’s impact evaluations or ‘Effectiveness Reviews’. esilience keeps getting bigger. What started off as an ambitious attempt to meld …

I’ve got the power! Calculating statistical power for matching models by simulation

Jonathan Lain ICT4D, Real Geek

Calculating statistical power – or working out how many people to interview before a survey – can be a challenge, especially if we want to use matching models to estimate projects’ impacts. In this blog post, we discuss how computer simulations might make power calculations easier and explain how we’ve tried this out in the evaluation team at Oxfam. How …