Category Archives: Uncategorized

A Dynamic Ordinal Item Response Theory Model with Application to Human Rights Data

by Chris Fariss

Keith Schnakenberg and I continue work on a paper in which we develop a measure the unobservable level of respect for human rights. I blogged about it earlier here. In the new version of the paper we build upon existing insights in the Bayesian measurement literature to develop a dynamic ordinal item-response (DO-IRT) model. We then assess the validity of the estimates obtained from the latent variable generated from the DO-IRT model with the estimates from an ordinal item-response (O-IRT) model and the original additive human rights scales. Below is a plot of the estimates of the latent physical integrity variable (see the paper for a similar plot of latent empowerment variable):

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R function for sorting NAs and data in each row of a Matrix

by Chris Fariss

# —– naSortMatrix function —————————— #
# —– by Chris Fariss ———————————— #
#
# Takes a data frame or matrix as an argument
# and returns another matrix after moving any NAs
# within each matrix row to the right of the data
# in that row without changing the order of the
# data. Also calculates the time taken to complete
# the sort and saves it as a global variable:
# naSortMatrix.time
#
# Just copy and paste this during an R session to
# use the function
#
# ——————————————————– #
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A Beautiful Image of the Global Social Network

by James Fowler

We should do one of these for the picture friend network!  Read about the image here.

Professor Craig McKenzie, Monday @ HNG

Monday, Craig McKenzie will be presenting his work.  Join us.  –Mike

McKenzie is a professor in the Department of Psychology and is also on faculty at the Rady School of Management.

Check out his research.  It’s pretty interesting.

http://psy2.ucsd.edu/~mckenzie/

http://management.ucsd.edu/faculty/directory/mckenzie/


Do Tweets Change Your Beahvior?

by James Fowler

Nicholas Christakis and I tackle this question with a little from a little help from Alyssa Milano….

http://www.cnn.com/2010/OPINION/11/16/fowler.christakis.tweeting/

 

Altruism and Political Participation

Posted by Peter Loewen

Understanding why people vote is a central concern of political science and democracy. Since elections are the central institution of a democratic society and since voting is the most widespread way of participating in an election, this centrality is quite sensible, obvious, and well-deserved. Despite this, we still don’t know a lot about why people vote.

I wanted to flag two new publications that go a little ways to explaining this better. The first is a paper I’ve just had come out in the CJPS. It’s largely derivative of Fowler’s early work (some of it with Kam) on the relationship between altruism and voter turnout. The second is a joint work with Fowler and Dawes (who else?!?).

James’ argument in those earlier papers (which is in turn pretty similar to Jankowski and Edlin et al) says that if you are concerned about other people (and you are not concerned about everybody equally), then you can be motivated to vote. Even though your vote is a very marginal contribution to any party’s winning, it is a marginal contribution that accrues to potentially millions of people. In other words, altruists should vote. However, three qualifications are important (and possibly obvious). First, you have to be willing to incur a cost to help those people. Second, the group about whom you are concerned has to be large enough for the act to be worthwhile. Third, you have to think that your vote will make those people better off. In other words, the party for which you cast your ballot has to intend to help those for whom you are concerned.
These two papers contribute to this literature in a few ways. First, the Canadian paper shows that altruism interacts with group size to increase turnout. This speaks to the second qualification above. The second paper, coming out in the Journal of Politics, shows that the type of social preference an individual has matters for whether they will participate in politics. Specifically, we argue and show that those who have utilitarian preferences have an increased likelihood of participating in politics, but those who have Rawlsian preferences do not. The reasoning is pretty simple: voters recognize that modern politics is most often about maximizing general welfare rather than bettering the lot of the worst off. See the third qualification above.
A final note: both papers use dictator games, behaviour in which has been shown to be heritable. So perhaps what we’re really doing is tracking down more mechanisms for the genopolitics end of the enterprise.

Vote, your neighbors are watching

By Mike Rivera

A recent NY Times Article reminds us of the effectiveness of social pressure on political behavior.  Check it out.