May 2006

Dirichlet Spaces and Metropolis Traces

Drew Thomas

A problem I've had come up again and again is the ability to explore a space bound by a Dirichlet prior with a Metropolis-type algorithm. I've yet to find a satisfactory answer and I'm hoping someone else will have some insight.

The research question I have deals with allocating patients to hospitals, considering the effect of the number of beds - one example of the "supply-induced demand" question. (The analysis is being done under Prof. Erol Pekoz, who's visiting Harvard Stats this year.) Conjugate...

Inheritance Laws

Jason Anastasopoulos, guest blogger

Question: Many political philosophers that focused on questions of property (including Plato) believed that equality of conditions were necessary for the development of a virtuous citizenry and virtuous leaders. The key to creating this equality of conditions, they argued, was the implementation of strict inheritance laws limiting the transfer of wealth from one generation to the next. Does anyone know of any quantitative models or empirical studies that examine the interaction between social stratification and inheritance laws...

It's summer!

It's the end of the term for both Harvard and MIT... so in view of the fact that we on the authors committee are about to embark on summers of tireless dedication to research while scattered to the far reaches of the planet, posting to this blog will be reduced until fall.

A special thanks to the loyal readers and commenters of this blog -- you folks have made this year a really rewarding experience for us. We won't stop posting, so do hope you still stop by occasionally and are still with us when we resume on a full schedule at the end of the summer.

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Reactions To The Virginity Pledge Study

Drew Thomas

Harvard School of Public Health doctoral candidate Janet Rosenbaum has been in the news lately, following the publication of her study of virginity pledges in the American Journal of Public Health, as well as her recent IQSS seminar. (Full disclosure: Janet is a friend of mine. I'll address her as Ms. Rosenbaum for this entry.) Since it's certainly a hot topic, it's no surprise how much attention her findings have received; first, the big news agencies picked it up, then the blogosphere took their shift - mainly over the "controversy" resulting from the...

Communication, Anyone?

Jim Greiner

The course I co-taught this semester on Quantitative Social Science & Law has come to an end. There were a lot of “lessons learned” in the class, both for the students (at least, I hope so) and for the teaching staff (more definitely). Of all of these lessons, one sticks in my head: we ought to focus on teaching quantitative students how to communicate with folks without formal statistical training.

Some quantitative folks will graduate and spend the rest of their lives talking to and working with only quantitative people. Some, but not...

A bit of google frivolity

Amy Perfors

Google has just come out with a new tool, Google Trends, which compares the frequencies of different web searches and thus provides hours of entertainment to language and statistics geeks like myself. In honor of that -- and, okay, because it's nearing the end of the term and I'm just in the mood -- here's a rather frivolous post dedicated to the tireless folks at Google, for entertaining me today.

Some observations:

1) One thing that is...

Statistical Discrimination in Health Care

Sebastian Bauhoff

This blog has frequently written about testing for discrimination (see for example here, here, and here). This is also a hot issue in health care. In health care there is a case for 'rational' discrimination' where physicians respond to...

An Intoxicating Story

From Wikipedia's entry on the t-test:

The t-statistic was invented by William Sealy Gosset for cheaply monitoring the quality of beer brews. "Student" was his pen name. Gosset was statistician for Guinness brewery in Dublin, Ireland, hired due to Claude Guinness's innovative policy of recruiting the best graduates from Oxford and Cambridge for applying biochemistry and statistics to Guinness's industrial processes. Gosset published the t-test in Biometrika in 1908, but was forced to use a pen name by his employer...

Running Statistics On Multiple Processors

Jens Hainmueller

You just bought a state-of-the-art PC with dual processors and yet your model still runs forever? Well, your statistical software is probably not multi-threading, meaning that despite the fact that your computer actually has two processors, the whole computation runs only on one of them. Don’t believe me? Well check your CPU usage, it's probably stuck at 50 percent (or less).

You might ask why statistical software doesn't use both processors simultaneously. The fact is that splitting up computations to two or even more processors is a non-...

Coarsened at Random

Jim Greiner

I’m the “teaching fellow” (the “teaching assistant” everywhere but Harvard, which has to have its lovely little quirks: “Spring” semester beginning in February, anyone?) for a course in missing data this semester, and in a recent lecture, an interesting concept came up: coarsened at random.

Suppose you have a dataset in which you know or suspect that some of your data values are rounded. For example, ages of youngsters might be given to the nearest year or half-year. Or perhaps in a survey, you’ve gotten some respondents’ incomes only within...

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