This is a talk I gave this week in Advanced Biostatistics at McGill. The goal was to provide an gentle introduction to Bayesian methodology and to demonstrate how it is used for inference and prediction. There is a link to an accompanying R script in the slides [Read more...]

I recently posted about coefficient plots, discussing my approach and providing some example R code to create the graphs. I had the good fortune of hearing Amanda Driscoll give a talk recently, and she made a small, but really nice … Continue rea... [Read more...]

One popular trend in presenting results is the "coefficient plot," an alternative to the table of regression coefficients. I am seeing this a little more often in political science research and have received a few requests for code, so I … Contin... [Read more...]

It is quite common in political science for researchers to run statistical models, find that a coefficient for a variable is not statistically significant, and then claim that the variable "has no effect." This is equivalent to proposing a research &#8... [Read more...]

Some scholars suggest that multiply imputing an outcome variable is incorrect. I use intuition and simulation to argue that multiply imputing outcomes can drastically improve estimates, even in the case of non-ignorable missingness. Continue reading &#... [Read more...]

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Earlier, I discussed the nice properties of bow tie plots for visualizing and understanding inferences from simple randomized treatment experimental designs. R code to quickly create these plots is available here. You can use the command source("htt... [Read more...]

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In data analysis it is often nice to look at all pairwise combinations of continuous variables in scatterplots. Up until recently, I have used the function splom in the package lattice, but ggplot2 has superior aesthetics, I think anyway.Here a fe... [Read more...]

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Roger Koenker, a quantile regression crusader, has an R package that implements the procedure. It is called quantreg, and it is documented here. This package has apparently been around for quite some time, but I was only recently turned on to quantile ... [Read more...]