Statistical Rethinking

10 Counting and Classification

All over the world, every day, scientists throw away information. Sometimes this is through the removal of “outliers” cases in the data that offend the model and so are exiled. More routinely, counted things are converted to proportions before analysis. Why does analysis of proportions throw away information? Because 10/20 and 1/2 are the same proportion, one-half, but have very different sample sizes. Once converted to proportions, and treated as outcomes in a linear regression, the information about sample size has been destroyed.

It's easy to retain the information about sample size. All that is needed is to model what has actually been observed, the counts instead of the proportions. No one has ever observed ...