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Archive of posts filed under the Multilevel Modeling category.

Estimating and summarizing inference for hierarchical variance parameters when the number of groups is small

Chris Che-Castaldo writes: I am trying to compute variance components for a hierarchical model where the group level has two binary predictors and their interaction. When I model each of these three predictors as N(0, tau) the model will not converge, perhaps because the number of coefficients in each batch is so small (2 for […]

The UN Plot to Force Bayesianism on Unsuspecting Americans (penalized B-Spline edition)

Mike Spagat sent me an email with the above heading, referring to this paper by Leontine Alkema and Jin Rou New, which begins: National estimates of the under-5 mortality rate (U5MR) are used to track progress in reducing child mortality and to evaluate countries’ performance related to United Nations Millennium Development Goal 4, which calls […]

Multilevel marketing as a way of liquidating participants’ social networks

Here I’m using the term “liquidate” in the economics sense (conversion of an asset into cash) rather than the Rocky-and-Bullwinkle sense of the word. Here’s the story: Katherine Chen writes: An executive summary version of Ackman and Dineen’s Powerpoint analysis underscores the potential impact of DSOs [direct selling organizations] upon distributors’ networks: Recruiting family members, […]

The gradual transition to replicable science

Somebody emailed me: I am a researcher at ** University and I have recently read your article on average predictive comparisons for statistical models published 2007 in the journal “Sociological Methodology”. Gelman, Andrew/Iain Pardoe. 2007. “Average Predictive Comparisons for Models with Nonlinearity, Interactions, and Variance Components”. Sociological Methodology 37: 23-51. Currently I am working with […]

Postdoc position on psychometrics and network modeling

Francis Tuerlinckx announces that he and Denny Borsboom have a joint postdoctoral position. It sounds really cool: The position is in the Research Group of Quantitative Psychology and Individual Differences at the University of Leuven (Belgium) and involves frequent travel to and contact with the Psychological Methods group in Amsterdam. The research of the postdoc […]

Schiminovich is on The Simpsons

OK, fine. Maybe they could work Stan on to the show next? I thought I could retire once I’d successfully inserted the phrase “multilevel regression and poststratification” into the NYT, but now I want more more more. Maybe a cage match between Stan and Mister P on the Itchy and Scratchy show?

Typo in Ghitza and Gelman MRP paper

Devin Caughey points out a typo in the second column of page 765 of our AJPS paper. Here’s what we have: The typo is in the third line of the second paragraph above. Where it says y^*_j = y.bar^*_j n_j, it should be y^*_j = y.bar^*_j n^*_j. One frustrating system of the current system of […]

The Employment Nondiscrimination Act is overwhelmingly popular in nearly every one of the 50 states

The above graph shows the estimated support, by state, for the Employment Nondiscrimination Act, a gay rights bill that the Senate will be voting on this Monday. The estimates were constructed by Kate Krimmel, Jeff Lax, and Justin Phillips using multilevel regression and poststratification. Check out that graph again. The scale goes from 20% to […]

How best to compare effects measured in two different time periods?

I received the following email from someone who wishes to remain anonymous: My colleague and I are trying to understand the best way to approach a problem involving measuring a group of individuals’ abilities across time, and are hoping you can offer some guidance. We are trying to analyze the combined effect of two distinct […]

Can’t Stop Won’t Stop Mister P Beatdown

Ben Highton and Matt Buttice point us to this response addressing some of the issues Jeff Lax raised in his most recent MRP post. P.S. Jeff replies in comments: It sounds like we’ve converged. They acknowledge MRP performance is significantly better on average than reported in their new paper in PA and yet performance variation […]