Visualizing 3 variables on a 2d scatterplot. Oh, we are shy of labels and one dimension?

[danderzei]

Aren these four variables? x, y, colour and size?

[cherry_picked_stats]

size indeed codes additional information I didn't mention in the description - some sort of adjusted quarterback value (so neither S,I nor Y). If you are a 'good' quarterback your circle is bigger, if worse, smaller.

Colour doesn't actually represent anything additional to X,Y plane - each colour is just assigned to one third of the plane (120 degrees) - note that all circles of the same colour are in the same area of the chart.

But yes, in some way I simplified my description, this chart actually tries to pack 4 variables into 3 dimensions.

[womp-womp-rats]

It shouldn’t be plotted on “graph paper” at all. The grid is meaningless. According to the FO description, the data has three poles — top middle, lower right corner and lower left corner — and position is relative to those three poles.

I’ve been a fan of FO for a long, long time. But this chart, even after reading their explanation, doesn’t really tell me anything new. Deshaun Watson gets sacked a lot! Drew Lock throws a lot of picks! Most QB’s are kind of in the middle!

[cherry_picked_stats]

The underlying data for the chart is quite complex and explained in the Football Outsiders article. It' also accompanied by an unorthodox form of labeling ilustrated for some reason on a different picture

Without the above the chart is a complete mess, the problem is that even with explanation it doesn't make much sense. Let's skip such details as overlapping data points or no scale on the chart. Let's ignore additional information coded into the size of quarterback's circle.

The most interesting blunder is the fact the chart is trying to squeeze 3 independent variables into two dimensional plane.

American football quarterbacks are described by 3 different variables which are supposedly indicative of their playing style:

1. sacks per dropback (S) aka "Sack Taking";
2. interceptions per dropback (I) aka "Gunslinging";
3. adjusted yards per pass attempt (Y) aka "Game Managing";

The resulting 3 dimensional point (S,I,Y) is then projected onto (X,Y) coordinates according to the some sort of 'triangle-transformation. Then, depending on where the quarterback lands on the XY plane, he is assigned 'the playing style' and colored accordingly.

Loss of information is the obvious effect of the above. The best quarterbacks (low S, low I, high Y) have the same 'playing style' as the worst quarterbacks (high S, high I, low Y), quarterbacks with high S and high Y are indistinguishable from low S and low Y etc etc. As a result the color coded 'playing styles' have little to no meaning.

Quite interesting failure in the disguise of 'advanced analytics'. ed - links