Marc F. Bellemare Posts

Several European countries also tax sugary drinks, but, as with Mexico, it’s tough to tease out whether, or how much, the taxes affect consumption. Marc Bellemare, assistant professor in the department of applied economics at the University of Minnesota, took a close look at soda sales data (from Euromonitor International, which tracks sales of an astonishing array of food items around the world). He concluded that, depending on how you parse the data, you could claim anything from no impact to about a 2.6 percent decrease.

“In academic parlance, the results are not ‘robust,'” Bellemare says. …

The lack of a clear correlation doesn’t mean sugary drinks aren’t implicated in obesity and disease. … We cannot be sure, not by a long shot, that a tax on soda will result in improved public health.

From a longer column by Tamar Haspel in the Washington Post last week. A few weeks ago, Tamar got in touch with me telling me she had gotten her hands on Euromonitor data for soda sales (supplemented with information about soda taxes in Europe), and she asked me whether I could figure out whether taxes appeared to cause any decrease in soda sales.

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):

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.