UPDATED 11/21/23
RealClearPolitics maintains a running tally of presidential election polls (among many others). RCP has also assessed the pro-Democrat or pro-Republican bias of the final presidential-election polls issued by major pollsters in 2016 and 2020. On average, the polls were biased toward the Democrat nominee by 2.3 percentage points.
As the pollsters release their results, I adjust Trump’s lead/deficit for bias. I then construct a moving average of the adjusted results, where the average represents Trump’s adjusted margin for the 10 most recent polls (taking the mid-point of each polling period as the date of each poll).
I then convert that 10-poll average to an estimate of Trump’s share of the two-party popular vote. For example, an average margin of +4 indicates a 52-48 split of the popular vote, that is, Trump gets 52 percent of the popular vote.
Finally, I apply my algorithm for the relationship between the GOP candidate’s share of the electoral vote and his share of two-party popular vote.
The estimates of popular-vote and electoral-vote shares don’t account for the margin of error in pollsters’ findings or the margin of error in my estimate of electoral votes. But the movement of the estimates may be taken as indication of the movement in voters’ preferences between Trump and Biden (or whoever might become their parties’ nominees). It is that movement which I will report from time to time.
Here is the first report, which begins with a clutch of polls that were completed in mid-August, when polling season seems to have begun in earnest:
Politics and Prosperity 