The New York Times has an article today ("For Drug Makers, a Downside to Full Disclosure") discussing the recent creation of archives for pharmecutical clinical trial data, including data from trials that did not result in publications. This effort is an attempt to deal with the age old problem of publication bias, a problem supposedly identified by the ancient Greeks, as described in a letter to the editor of Lancet by Mark Pettigrew:

The writings of Francis Bacon (...

This is a common question, commonly misunderstood. It certainly does seem like MI makes up data, since if you look at the 5 or so imputed data sets, the missing values are indeed filled in. But in fact, the point of MI has nothing to do with making up data, and everything to do merely with putting the data in a more convenient format.

The fact is that the vast majority of our statistical techniques require rectangular data sets, and so data that look like swiss cheese make it really hard to do anything sensible with directly. Listwise deletion, where you excise horizontal...

The Program on Survey Research at Harvard is hosting an afternoon conference tomorrow on the challenges of surveying multiethnic populations:

Surveying Multiethnic America

May 11, 2007
12:30 – 5:00

Institute for Quantitative Social Science
CGIS N-050
1737 Cambridge St.
Cambridge, MA 02138

Across a variety of different academic disciplines, scholars are interested in topics related to multiethnic populations, and sample surveys are one of the primary means of studying these populations. Surveys of...

Amy Perfors

This may not be new to anybody but me, but recent news at UNC brought the so-called "Achievement Index" to my attention. The Achievement Index is a way of calculating GPA that takes into account not only how well one performs in a class, but also how hard the class is relative to others in the institution. It was first suggested by Valen Johnson, a professor of statistics at Duke University, in a paper in Statistical Science titled "An Alternative to Traditional GPA for Evaluating Student...