To help show how to use
ggplot2 to solve problems, and to better
understand the grammar of graphics, I’ll use a real, complicated data
example: U.S. Medicare cost and outcome data. See Medicare Data for
Let’s start with a simple example: average mortality and readmission rates for three common medical conditions. We’d like to compare national treatment effectiveness statistics for three common diseases. This is a fairly simple data set: there is one dimension (the readmission rate), three conditions (Heart Attack, Heart Failure, and Pneumonia), and one factor variable (Measure) ...