Blog

What's your optimal GPA?

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...

Peress on "Estimating Proposal and Status Quo Locations Using Voting and Cosponsorship Data"

Please join us this Wednesday, December 3rd when Michael Peress, Department of Political Science, University of Rochester, will be presenting, "Estimating Proposal and Status Quo Locations Using Voting and Cosponsorship Data". Michael provided the following abstract,

Theories of lawmaking generate predictions for the policy outcome as a function of the
status quo. These theories are difficult to test because existing ideal point estimation techniques do not recover the locations of proposals or status quos. Instead, such techniques only recover cutpoints. This limitation...

Physics of politics

A physicist recently emailed me asking if I could help him access election data; he sent me one of his papers, which (to my astonishment) began "Most of the empirical electoral studies conducted by physicists . . .", followed by a string of citations. I had no idea physicists were studying elections! I suppose I should have known; from what my biologist friend tells me, physicists have been colonizing his field the way economists have done to much of social science. So I guess politics was next.

Reading a few articles in the "physics of politics" as a political scientist, one has...

Pigskin and Politics

Here's a paper in which the authors devised a clever way to gather data and answer an interesting question:

Pigskins and Politics: Linking Expressive Behavior and Voting
David Laband, Ram Pandit, Anne Laband...

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. the effect estimate...

Placebo effects and the probability of assignment to active treatment

I just finished reading an interesting paper on placebo effects in drug trials by Anup Malani. Malani noticed that participants in high probability trials know that they more likely to get active treatment (because of informed consent prior to the trial). They have higher expectations and hence should have higher placebo effects than patients in low probability trials. Malani compares outcomes across trials with different assignment probabilities and finds evidence for placebo effects. A related...

Goodrich on "Bringing Rank-Minimization Back In"

Please join us tomorrow, September 16th when we are excited to have Ben Goodrich (Government/Social Policy) presenting "Bringing Rank-Minimization Back In: An Estimator of the Number of Inputs to a Data-Generating Process," for which Ben has provided the following abstract:

This paper derives and implements an algorithm to infer the number of inputs to a data-generating process from the outputs. Previous working dating back to the 1930s proves that this inference can be made in theory, but the practical difficulties have been too daunting to overcome. These obstacles can...

Plotting Survival Curves with Uncertainty Estimates

One of the pesky things I've found in my (limited) experience with survival analysis is that it's almost impossible to plot several survival curves in the same space and include measures of uncertainty without the entire plot becoming incomprehensible. So, to build on the great R discussions Ellie and Andy have provided in recent blog posts, I'd like to offer an extension of my own. I've created a...

Political Economy Students Conference

Dear students and colleagues,

We would like to invite you to attend the Political Economy Student Conference, to be held on April 17th in the NBER premises, in Cambridge, MA. The conference is an opportunity for students interested in political economy and other related fields to get together and discuss the open issues in the field, know what other people are working on, and share ideas. The program of the conference can be found at:

http://www.stanford.edu/group/peg/april_2008_conference/...

Political Methodology Career Award - Call for Nominations

Simon Jackman sent around the following today on behalf of the Society for Political Methodology:

The Society for Political Methodology will award its first Political Methodology Career Award this year, to recognize an outstanding career of intellectual accomplishment and service to the profession in the Political Methodology field. The award committee -- Simon Jackman (chair), Elisabeth Gerber, Marco Steenbergen, Mike Alvarez -- is calling for nominations for this award, due no later than Monday May 28, 2007. Nominations...

Political Statistics Blogs

Mike Kellermann

With the 2006 election coming up soon, here are a couple of blogs that might appeal to both the political junkie and the methods geek in all of us. Political Arithmetik , a blog by Charles Franklin from Wisconsin, is full of cool graphs that illustrate the power of simple visualization and non-parametric techniques, something that we spend a lot of time talking about in the introductory methods courses in the Gov Department. (On a side note, I think that the plots like...

Polling Super Tuesday

Another Tuesday, another primary election or twenty, and another opportunity for things to go wrong with pre-election polls. The super Tuesday states, which had not seen much attention from pollsters earlier in January, have seen a deluge of polls released in the last week, nicely summarized at the Mystery Pollster blog. As Mark Blumenthal's recent post points out, "Somebody's gonna be wrong". The amount of dispersion present in the recent polls on both sides of the election exhibit is far more than can be...

Polling the Iowa Caucuses

The presidential caucuses in Iowa will be held tonight, giving us our first "official" measure of popular support for the candidates in each party. We've had lots of "unofficial" measures from polls taken over the past few months - over 50 polls taken since Labor Day are posted on pollster.com - but polling to predict the outcome of the caucuses (as opposed to polling designed to measure overall support for the candidates) presents a number of difficult problems.

The first of these problems, and the one that has received the most attention, is identifying likely caucus...

Polling the New Hampshire Primaries

New Hampshire voted last night, and managed to set off another frenzy of introspection among pollsters and pundits. On the Democratic side, public polls released after Iowa showed Obama leading Clinton by an average of about 10 points, but in the end Clinton of course edged out a narrow victory. The polls were much closer on the Republican side, but the "miss" on the Democratic side has already produced much concern about "New Hampshire's Polling Fiasco". Perhaps the witch-hunt that ensues whenever polls...

Pol Meth Conf I

The 14 papers presented at the 2005 Conference of the Society for Political Methodology, held July 21st-July 23rd in heavily air-conditioned rooms at Florida State, provided plenty of good fodder for discussion. I will focus on several I found especially provocative--and on which I could reasonably comment--in blog posts over the next few days.

Starting off the conference, Gary King's presentation of his paper Death by Survey: Estimating Adult Mortality without Selection Bias'' with Emmanuela Gakidou argued that we...

Pol Meth Conf II

Dan Hopkins, G4, Government (guest author)

Continuing with the matching theme on which I ended the post of two days ago, Alexis Diamond and Jas Sekhon presented a paper on genetic matching that claimed to be a significant improvement on past approaches. One of the challenges of matching is to weight each of the covariates so as to produce the optimal set of matches. Genetic matching uses a genetic algorithm to search across the set of possible weight matrices to find the weight matrix that minimizes some loss function. Of course, what exactly that loss function should be is...

Pol Meth Conf III, & GOV 2000

Pol Meth Conf III
Dan Hopkins, G4, Government (guest author)

Continuing the discussion of the recent Political Methodology Conference, throughout its first two days the notion of the conference as the "Second Annual Conference on Matching" was a running joke, and definitely a fair joke, although the two matching papers were, well, matched by two ideal point papers. So on to ideal points. Michael Bailey's paper tackled an important problem: because major figures across the different institutions of the federal government are faced with different policy decisions, it is hard to...

Pol Meth Conf IV

Dan Hopkins, G4, Government (guest author)

Continuing with the discussion of papers presented at the recent Political Methodology Conference, Kevin Quinn and Arthur Spirling's paper begins with the problem of identifying legislators' preferences in conditions of strict party discipline. To tackle this challenge, they applied a Dirichlet process mixture model and presented some interesting results about the intra-party groups observed in the British House of Commons. They backed up the groupings recovered from the model with significant qualitative work, and showed how qualitative...

Pop music is getting louder, possibly more boring (statistically speaking)

The NYT just alerted me to a paper by Joan Serra and coauthors demonstrating what we can learn about popular music with a big data approach. I'll leave it to you to interpret the trends they identify (music is getting louder, also more similar), but it was interesting and gave me a lot of ideas for how I could borrow some of this technology for my own research.

...

Positive Political Economy - Robert Erikson

Tomorrow afternoon, the Harvard-MIT Positive Political Economy seminar will be presenting at talk by Robert Erikson, professor of Political Science at Columbia University. He will be giving a talk entitled "Are Political Markets Really Superior to Polls as Election Predictors?". The seminar will meet on Thursday, April 26 at 4:30 in room N354 at CGIS North (this is also the room where the Applied Statistics workshop...

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