Nathaniel Rakich of FiveThirtyEight –
So far, it hasn’t been a great year for pollsters. The 2020 presidential primary polls had a weighted average error — i.e., the absolute difference between a poll’s margin (between the top two candidates) and the actual vote share margin — of 10.2 percentage points. That’s roughly tied with the 2016 presidential primaries for the biggest error in primary polling this century.
We encourage you to check out the new ratings, especially when a new poll comes out and you want to gauge its reliability.