People are wrong in saying the polls were terrible this year. They weren't great, but they weren't terrible.

Biggest takeaway: most of the polling errors were favorable to Trump, which means that the issues of 2016 were not fixed: pollsters are still failing to properly sample and/or adjust for conservative voters. That's something they will have to examine much more.

However, there's also the confounding factor of voter suppression by the Trump administration and GOP state governments, including slow-walking or disallowing voting by mail, sabotaging the USPS, and shit-talking voting by mail. Pollsters and forecasters, including FiveThirtyEight, made no attempt to adjust for that, because they had no idea how.

That said, election day went very smoothly and turnout beat records, so I doubt it was much of a factor in the end.

The attached image consists of the main bottom lines I took away from my analysis. My data is linked in my Dropbox.

All prediction and polling data (using their adjusted average) was taken from FiveThirtyEight.

https://www.dropbox.com/s/6246ajvz2s4o654/Polling%20and%20Forecasting%202020.xlsx?dl=0