Political Patchwork Chart

I’ve built a new chart building on previous work with British Election Study data and the Political Compass (two major axes of political variation). A great chart needs no explanation. But want != need.

Visual metaphor: think of each party as holding up an opened “umbrella” — a coloured surface whose height at every point reflects the average abstract appeal (“would you ever vote for?”) for voters at that point of the Political Compass.

Previously, the way I’ve visualised this sort of thing is to have one graph per umbrella side by side or overlaid them on top of each with the colours merging. Due to inferior human cerebral hardware, the results can be hard to read.

So what I’ve done here is to put all the umbrellas on one chart, but now we’re looking down from above and we only see the uppermost surface at any given point.

Upside, pretty chart with nice clean lines. Downside, we’re throwing away a lot of information. For instance, the “umbrellas” for UKIP and TIG were calculated, they’re just completely obscured by higher “umbrellas”.

A more subtle issue is that when you look at the Lib Dem orange swatch of colour you’re not seeing “the areas where people would like to vote Lib Dem” — you’re seeing “the areas where people would like to vote Lib Dem *that are uncontested by any other party*”.

(Light is Very Likely to vote for party, Dark is Very Unlikely)

The Lib Dem vote midpoint — on this chart scale — is actually Socially Liberal:Economic Centre/Economic Centre-Left. But they are contested on the Economic Left by the Greens and Labour — while on the Socially Liberal:Economic Right the Conservatives have actively ceded ground.

And the same is true for the Brexit Party. What we’re seeing is not “where their votes are” but “which territory do they have to themselves”. And that’s partly because we’re not seeing the variation in how enthusiastic voters are about the *best* choice. We can see that in this sensually-terrifying half-Cronenberg half-Doctor Who chart below:

Is the British population evenly distributed across this space? I’ve put considerable time into tinkering with the Political Compass data to make the distribution as flat, even and uniform as possible without significantly deforming it.

The answer is “mostly” — the top 50% of the chart has 50% of the British Election Study sampled people (total N~90,000+) — and so on for any vertical/horizontal slice.

But where the axes interact — which they do less than people reflexively assume and more than is convenient for political scientists — there is structure that can’t be easily massaged out.

And that’s why I’ve added subtle contour lines. Note that this is pretty fine structure — e.g. the bottom right quadrant contains 24.2% of the sample (rather than 25%). So the Lib Dem dominance — viewed in terms of ares — as a fraction of the UK voting population is inflated, but probably only by ~5%.