shira mitchell

@shiraamitchell.bsky.social

survey statistician at blue rose research 🏕

blog post: poststratification without population level information Poststratification uses population data on X to help estimate a population mean E(Y). But sometimes population data on X isn't available: In 2016 Andrew asked pollsters to poststratify on party ID, but how ?

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AAndrew Gelman et al.@statmodeling.bsky.social · last mo.

Survey Statistics: poststratification without population level information statmodeling.stat.columbia.edu/2026/07/21/s...

blog post: quantifying uncertainty in ranked choice voting polls RCV uses rankings to get a winner by instant runoff. Polls estimate rank probabilities with uncertainty. Unlike with non-RCV, even in random samples a plurality of uncertainty mass can get an incorrect winner.

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AAndrew Gelman et al.@statmodeling.bsky.social · 2mo ago

Survey Statistics: quantifying uncertainty in ranked choice voting polls statmodeling.stat.columbia.edu/2026/07/14/s...

blog post: perfect collinearity in the sample but not in the population Two variables are perfectly collinear in your sample, so you drop one. You use your model to predict in the population. What can go wrong ? Let's talk thru a Census Bureau toy example from BDA2.

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AAndrew Gelman et al.@statmodeling.bsky.social · 2mo ago

Survey Statistics: perfect collinearity in the sample but not in the population statmodeling.stat.columbia.edu/2026/06/23/s...

blog post: using MRP in later analyses (pride edition) happy pride ! 🌈 @jeffreylax.bsky.social & Phillips 2009 used MRP to estimate state-level public opinion about policies affecting gays and lesbians. They then use this as a predictor of whether the state adopts the policies.

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AAndrew Gelman et al.@statmodeling.bsky.social · 3mo ago

Survey Statistics: using MRP in later analyses (pride edition) statmodeling.stat.columbia.edu/2026/06/16/s...

blog post: should MRP workflow include LOCO-CV ? Individual-level loss orders models differently than the population-level loss we want judging MRP. To get population-level loss, use out-of-sample classical poststratification to compare with MRP. How to split data ? LOCO = leave one cell out.

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AAndrew Gelman et al.@statmodeling.bsky.social · 3mo ago

Survey Statistics: should MRP workflow include LOCO-CV ? statmodeling.stat.columbia.edu/2026/06/09/s...