The poll is largely in line with the average poll since April that puts Biden 6 points ahead of Trump nationally.
The stability of the polls is record high. The bid advantage is the most stable in a sitting race since at least 1944. That may mean it will be more difficult to change the course for the race ahead, although this remains more than close enough for both candidates to easily win.
To know this, I went back and looked at how all the national polls differed from January to early May of the election year.
This year, 95% of all individual polls have so far shown a result within 6 points of the average. That's basically what to expect if you took a lot of polls and the race didn't move (ie the only shifts are statistical noise from sampling). Historically, there is a ridiculously small range.
The previous low for a similarly constructed 95% confidence interval was 8 points (2012). The median cycle contained a 95% interval of 13 points from the mean of the polls. In other words, about twice the reconciliation we have seen so far in 2020.
Sometimes, of course, the results can be even greater than the median cycle. Lyndon Johnson had everything from a 35-point advantage to a lead of more than 60 points over Barry Goldwater in the first months of 1964. Jimmy Carter opened 1980 with a 30-point or greater lead in some of Ronald Reagan's polls. In early May, the lead was down to single digits, and he even drew Reagan in a few polls.
There seems to be a certain correlation between early voting movement and how well early voting predicts the results. In cycles with less early movement than normal, the average difference between the polls over the four months and the final results has been 5 points. In cycles with greater early movement than normal, the average difference between the polls during that time and the final result has been 14 points.
In other words, it would be appropriate for previous patterns if the opinion polls are now close to the results. This is in line with what you can expect, given that more voters have a stronger view of Trump than any other sitting since at least 1980 (when the question was first asked), as I mentioned earlier.
The obvious catch here is that a 5-point difference between where the polls have been and the November result can be huge this year. Biden increases by just 6 nationally on average. A 5-point shift in Trump's direction would mean a 1-point victory by Biden in the popular vote. This could very well leave him on the wrong side of a popular vote and the electoral college. Remember that Trump lost by 2 points nationally in 2016 and still pulled a victory in the electoral college.
And we're just talking about the average here. The 1956 campaign, which saw limited shifts early, had Democrat Adlai Stevenson 10 points better than his early polling station.
The bottom line is that although stability in the 2020 race so far projects minimal movement from here on out, it does not in any way guarantee Biden a victory. There are still a number of results possible.