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Berk Ozler's blog

Weekly Links March 20: Giving away TOMS shoes, evaluating anti-terrorism interventions, Ben Olzer, and more...

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Bruce Wydick on the Impact of giving away TOMS Shoes: He gives kudos to TOMS for being open for evaluation and being responsive to findings, but what caught my eye was this observation: "The bad news is that there is no evidence that the shoes exhibit any kind of life-changing impact,..."

Why is Difference-in-Difference Estimation Still so Popular in Experimental Analysis?

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David McKenzie pops out from under many empirical questions that come up in my research projects, which has not yet ceased to be surprising every time it happens, despite his prolific production. The last time it happened was a teachable moment for me, so I thought I’d share it in a short post that fits nicely under our “Tools of the Trade” tag.

Response to Brown and Wood's "How Scientific Are Scientific Replications? A Response"

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I thank Annette Brown and Benjamin Wood (B&W from hereon) for their response to my previous post about the 3ie replication window. It not only clarified some of the thinking behind their approach, but arrived at an opportune moment – just as I was preparing a new post on part 2 of the replication (or reanalysis as they call it) of Miguel and Kremer’s 2004 Econometrica paper titled “Worms: Identifying Impacts on Education and Health in the Presence of Treatment Externalities,” by Davey et al. (2014b) and the response (Hicks, Kremer, and Miguel 2014b, HKM from hereon).  While I appreciate B&W’s clarifications, I respectfully disagree on two key points, which also happen to illustrate why I think the reanalysis of the original data by Davey et al. (2014b) ends up being flawed.

Friday links November 21

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Confusing a treatment for a cure

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A treatment is an instance of treating someone, say, medically. A cure ends a problem. Sometimes, the treatment is a cure. Other times, it just keeps the problem under control without curing it: if you remove the treatment, the problem comes back…
 

Taking Ethics Seriously: Response #1

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Yesterday, Martin Ravallion wrote a piece titled ‘Taking Ethical Validity Seriously.’ It focused on ethically contestable evaluations and used RCTs as the main (only?) example of such evaluations. It is a good piece: researchers can always benefit from questioning themselves and their work in different ways.

Introducing 'Ask Guido'

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This week we're introducing our new series that we decided to call 'Ask Guido.' Guido Imbens has kindly agreed to answer technical questions every so often and we are thrilled. For this first installment, Guido starts by answering a question about standard errors and the appropriate level of clustering in matching.
 

One question that often comes up in empirical work concerns the appropriate way to calculate standard errors, and in particular the correct level of clustering. Here is a specific version of the question that someone posed, slightly paraphrased:

Becoming a Man (and Good at Math)

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Although, I try to follow the research in my field regardless of where it is conducted, I usually don’t pick studies from the U.S. or other developed countries for discussion in this space. However, when the study involves interventions to improve various outcomes for adolescents, reports some encouraging findings, and may be applicable in the developing world, we can make an exception. So, today’s post is about a study that takes place in a public high school on the south side of Chicago…

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