Marc F. Bellemare Posts

One thing I often see authors doing in some of the papers I get to handle as an editor or comment on as a reviewer is using a Durbin-Wu-Hausman test–for the sake of brevity, I will just say “Hausman  test” throughout this post–to test for exogeneity. The idea for this post came from my reading of Jeff Woolridge’s article on the control function approach (more on that approach in a moment, and yes, the same Wooldridge who wrote what is perhaps the best microeconometrics text on the market) in the latest issue of JHR.

Typically, this is done in an effort to argue that some variable of interest is not really endogenous to the outcome of interest, and it proceeds as follows (note that I am describing a situation where researchers have to rely on observational data):

My colleagues and I recruited actual human subjects in Germany. We ran an actual clinical trial, with subjects randomly assigned to different diet regimes. And the statistically significant benefits of chocolate that we reported are based on the actual data. It was, in fact, a fairly typical study for the field of diet research. Which is to say: It was terrible science. The results are meaningless, and the health claims that the media blasted out to millions of people around the world are utterly unfounded.

From a fascinating article with the click-baity title “I Fooled Millions Into Thinking Chocolate Helps Weight Loss. Here’s How,” by John Bohannon on io9.

“But wait,” you say, “if this was all based on actual data and the finding wasn’t false, why are the findings meaningless?” Because of this:

Food historian and philosopher of science and technology Rachel Laudan, whose book Cuisine and Empire: Cooking in World History just came out in paperback this last month, has a great article in the latest issue of Jacobin magazine.

There are just too many excellent tidbits to Rachel’s article that I have to quote many of them. There’s this:

It is a mark of sophistication to bemoan the steel roller mill and supermarket bread while yearning for stone­ ground flour and brick ovens; to seek out heirloom apples and pumpkins while despising modern tomatoes and hybrid corn; to be hostile to agronomists who develop high-yielding modern crops and to home economists who invent new recipes for General Mills.

And this: