PURPLE AMERICA, PART 2….In the previous post I suggested that “purple” election maps would be perceptually more accurate if every county that gave more than 70% of its votes to a candidate were solid red or solid blue, and the purple spectrum was used only for counties that gave between 30% and 70% of their vote to each candidate. My thought was that anything over 70% represents a pretty polarized place, and only counties in the middle band can really be considered to have a serious mix of Democrats and Republicans.
Several people responded to my request for a map colored this way (thanks, everyone!), and the map below from Ryan Lohbauer seemed like the best match to what I asked for. My guess is that this represents the regional polarization of American politics more accurately than either the plain red/blue map (which makes polarization seem worse than it is) or the bland purple map (which makes it seem better than it really is). Needless to say, you can decide for yourself by looking at both maps.
NOTE: As several people pointed out, this map still doesn’t correct for the low population of red counties compared to blue counties. If you want to see a map that uses this color scheme and adjusts for county size, check out this page from Michael Gastner, Cosma Shalizi, and Mark Newman of the University of Michigan and scroll to the very bottom.