At the 2018 midterms, the last time US pollsters were tested in national elections, the Democrat margin was 1.1% better than predicted
Twelve days before what has become the biggest political betting event of all time it is worth reminding ourselves at how well US pollsters performed the last time they were tested in a real set of elections.
The above Real Clear Politics table gives quite a degree of confidence. The main elections taking place in November 2018 were for the House and as can be seen most of the final polls were in the right territory having Democratic margins within the margin or error. The big outlier was Rasmussen which had the Republicans ahead.
It is mostly the same pollsters who have been carrying out survey after survey on the the November 3rd election.
A factor that should give added confidence now is that with the huge level of early voting maybe a third of those sampled will have voted already and these are in effect forms of exit polls.
This is the current RCP table.
My money remains on Biden.