Splitting a Random Sample Along Some Control Variable to Get at Treatment Heterogeneity (Updated)

I teach the second-year PhD research seminar in the Department, and it’s that time of year again when students have to submit a draft of their second-year paper. In case you are not familiar with a second-year paper, it is essentially the widespread practice in applied economics and economics department of having students who are done with their first-year courses to write an entire publishable paper from start to finish.

As such, teaching the second-year paper involves reading a lot of drafts. One of the drafts I read last week did something that always baffles when I see it. This might be a simple question whose answer is obvious, so bear with me, but the practice is so common that I thought I would ask readers whether it is me who is missing something. The practice is as follows (note that I am positing all this for observational data, not experimental data): Continue reading

The Empirical Result Taking on the World By Complete Lack of Surprise


This paper presents results from a randomized controlled trial whereby approximately 1,000 One Laptop Per Child XO laptops were provided for home use to children attending primary schools in Lima, Peru. The intervention increased access and use of home computers, with some substitution away from computer use outside the home. Children randomized to receive laptops scored about 0.8 standard deviations higher in a test of XO proficiency but showed lower academic effort as reported by teachers. There were no impacts on academic achievement or cognitive skills as measured by the Raven’s Progressive Matrices test. Finally, there was little evidence for spillovers within schools.

The abstract of a new article (ungated) by Diether Beuermann and coauthors in the latest issue of the American Economic Journal: Applied Economics.

PhD Fellowships to Study Food Security at the University of Minnesota

Waite Library at Ruttan Hall (Source: UMN).
Waite Library in the Department of Applied Economics at the University of Minnesota (Source: UMN).

For those of you who (i) are thinking of going to graduate school, (ii) have an interest in food security, and (iii) happen to be US citizens (seriously, this is a real requirement; the last time I talked about this, I had about a dozen inquiries from non-US citizens…), I still have one, possibly two National Needs Fellowships from the  National Institute of Food and Agriculture‘s (NIFA) to award to prospective PhD students with an interest in food security. Thanks to our department’s rolling admissions deadline, it is not too late for you to apply for those fellowships. If you are interested, however, I urge you to (i) let me know via email as soon as possible, and (ii) apply as soon as possible for admission in September, since the funds have to be awarded before July 1, 2015.

Each fellowship provides the recipient with a three-year fellowship. The theme of the grant is food security broadly defined. So for example, a fellow could study any aspect of food security, from undernutrition in sub-Saharan Africa to food stamps in the US, and everything else in between. That said, for students interested in international development, the grant does include some money for international travel–not enough to fund data collection, but enough to fund exploratory field visits. Continue reading