The Best (and Worst) Pollsters

Spain is being flooded with election polls, but which should you trust? El País compiled the data, and we’ve recreated it here. The TL;DR: across all elections, most pollsters overestimate the left, but in national elections (the kind coming up), most overestimate the right. GAD3 has the best overall record, while 40dB, which conducts El País’s polls, is tops in the national votes. El País’s poll of polls is pretty damn good. And the CIS sucks.

How to read this table: MAE (mean absolute error) shows each pollster’s average error relative to the median error of all pollsters in each election. A negative number means the pollster was more accurate than the median; a positive number means it was less accurate. Bias shows the average direction of the pollster’s miss: “Left” means it overestimated left-wing parties, “Right” means it overestimated right-wing parties.
Chart: The BubbleSource: El PaísGet the data