The associated blog post also seems to use median and average interchangeably(?!): While the median federal income tax burden across counties is about $3,400

The associated blog post also seems to use median and average interchangeably(?!): While the median federal income tax burden across counties is about $3,400 the average tax burden across counties is $3,419 The distribution may be more normal than I assume, or the word "median" in the first graf may be a mistake. In either case, I too would love to see the median-based map.