I am looking for feedback on a graphical method I’ve devised for comparing groups.  I think it can be used for many different kinds of quantities, some of which I show on my website http://mason.gmu.edu/~bklinger/nationshome.html.

The plot shown below (and at http://mason.gmu.edu/~bklinger/Nations/elecmargin.html) summarizes how states voted in the recent presidential election.  Each box represents a different state, with states divided into two stacks depending on which candidate got a larger vote there.  The width of each box represents the percentage margin of victory of the candidate that won in that state.  The height of each box represents the total number voting for both candidates in that state.  Therefore the area of the box (= width times height) represents the the margin of victory in number of voters.

This representation shows several interesting features of an election at once.  The intensity of support for each candidate can be easily compared among states by looking at the widths which are aligned along a common vertical axis.  The box height represents the total number of voters living in a state in which a given candidate won.  This is similar (but with important differences) to the electoral college votes of that state.  The box areas give a measure of the importance of that state’s margin in building the national popular vote margin for a candidate.

One can see at a glance that about 40 million people voted in states that went strongly (> 10% margin) for Clinton, 25 million in states that voted strongly for Trump, and around 20 million in states that went narrowly (<2%) for Trump.  Clinton’s national total relied on a few states that were both populous and highly partisan, while Trump had a large number of low-population partisan states.   Collectively the states Trump won had substantially more voters than the Clinton states (75 million to 55 million) even though Clinton got more total votes.

I included the cumulative graph on the right of the stack in order to facilitate adding together the margins from different states in each stack.  This shows that just the 8 states which were the most pro-Clinton accumulated as much of a margin (number of votes) for her as all the pro-Trump states did for Trump.

The Washington Post and Wikipedia have been showing cartograms of the US to represent the vote; the stack of boxes shown here loses the geographical information but makes it easier to see the relationship between numbers.  I think this conveys a lot of information quickly and efficiently and is a good tool for understanding and comparing elections… but I’m curious to see what other people think.


Data available here.