# Posts

### The Good, the Bad and the Ugly in the CDC's Face Mask Study

While perusing the news, I read eagerly about the CDC’s recent study examining associations between county-level mask mandates and COVID-19 growth rates. This study has already been the subject of angry retorts from the restaurant industry due to the CDC’s claim that restaurant closures reduced COVID-19 spread.

You can access RBloggers, an R consortium of bloggers, at this link.

### Why People Are Doubting the AstraZeneca Vaccine Report

In this blog post, I use Gelman and Loken’s garden of forking paths analysis to construct a simulation showing why skepticism of AstraZeneca’s vaccine results is warranted at this early stage.

### A More Realistic P-Value for the Pfizer Vaccine Report

I start with Eric Novik’s excellent blog post on how to calculate the relevant statistics for the vaccine, i.e. vaccine efficacy (VE). This is defined as: $VE = 1 - \frac{p_t}{p_c}$

### Why You Should Be Careful About the MaterniT 21 Test

My wife and I have been faced with a decision in our pregnancies that has always caused me some consternation: should we take the MaterniT 21 test to see if our baby might have Down’s syndrome (trisomy 21) or other genetic abnormalities?

### What Panel Data Is Really All About

We’ve all been in that seminar where the author puts up a slide containing regression coefficients, and buried in the bottom line of the table we can see little Ys and Ns indicating the kind of panel data model employed.

### A Proposed Model for Partial Identification of SARS-CoV2 Infection Rates Given Observed Tests and Cases

For an up to date version of this model, please see our paper at https://osf.io/preprints/socarxiv/jp4wk/.

### Simulating Conjoint Survey Experiments

Background Conjoint survey experiments have become more popular in political science since the publication of Hainmueller, Hopkins and Yamamoto (2014). However, analysis of the statistical of power of conjoint experiments is difficult using standard parametric techniques because of the use of multiple treatments, interaction effects and paired vignettes.

### idealstan: an R Package for Ideal Point Modeling with Stan

This is a paper that was presented at the StanCon2018 conference on Bayesian inference with the Stan Hamiltonian Markov Chain Monte Carlo (MCMC) method. Video of my talk is available here.