January 2007

The Role of Sample Size and Unobserved Heterogeneity in Causal Inference

Here is a question for you: Imagine you are asked to conduct an observational study to estimate the effect of wearing a helmet on the risk of death in motorcycle crashes. You have to choose one of two different data-sets for this study: Either a large, rather heterogeneous sample of crashes (these happened on different roads, at different speeds, etc.) or a smaller, more homogeneous sample of crashes (let's say they all occurred on the same road). Your goal is to unearth a trustworthy estimate of the treatment effect that is as close as possible to the `truth', i.e.

Statistical porridge and other influences on the American public

In this past Sunday’s New York Times Book Review, Scott Stossel covers a book by Sarah E. Igo, a professor in the history department at the University of Pennsylvania. The Averaged American – which I haven’t read but plan to pick up soon – discusses how the development of statistical measurement after World War I impacted not only social science, but also, well, the average American.

Stats of the Union

Dr. King, Esteemed Faculty, Members of the Advisory Board, My Fellow Stats Brats:

The rite of custom brings us together at a defining hour when decisions are hard and courage is needed. We enter the year 2007 with large endeavors under way and others that are ours to begin. In all of this, much is asked of us. We must have the will to face difficult challenges and determined reviewers, and the wisdom to face them together.

The Goal of Causal Inference

I’ll be giving the talk at the Gov 3009 seminar in early February, and I’ll be presenting a paper I’m writing with Don Rubin on applying the potential outcomes framework of causation to what lawyers call “immutable characteristics” (race, gender, and national origin, for example). I’ll be previewing some of the idea from this paper on the blog.

Mother Nature Estimates Using...?

So it's finally getting cold in Boston after some days that resembled Spring more than anything. Outside the buildings, smokers in T-shirts and flip-flops? The first flowers blooming?? But it's not all lost: I was just reading that an early Spring or a short interval of warm temperatures doesn't really matter for plants and animals. Plants just grow new buds or skip a year. Animals adjust their sleep patterns. But maybe Mother Nature is also smart about predicting when it's the right time to wake up.

Applied Statistics Workshop

The Applied Statistics Workshop will resume for the spring semester on January 31, 2007. We will continue to meet in the CGIS Knafel Building, Room N354 on the third floor at noon on Wednesdays. The Workshop has a new website that has the tentative schedule posted for the semester. We will be moving the archives of papers from the previous semesters to the new site in the coming weeks, so you can track down your favorite talks from years past.