Joe Biden, the presumptive Democratic nominee for president, leads President Trump in most national polls, and surveys conducted even this far out have tended to roughly resemble the eventual general election results, as FiveThirtyEight’s Geoffrey Skelley explained in an article this week. Of course, national polls measure the national popular vote, which is really only indirectly related to who will win the White House — Democrats have won the popular vote but lost the Electoral College in two of the last seven elections and could do so again in 2020. U.S. presidential elections are really a contest of states.
Several polling firms released surveys of Florida, Michigan, Pennsylvania and Wisconsin in April. Former President Barack Obama carried all four states in 2012. Trump flipped all four in 2016 (as well as Ohio and Iowa, neither of which has much recent polling.) And Biden appears to lead in all four now. (North Carolina, which has gone Republican in both of the last two cycles, was also polled pretty often in April, with Trump and Biden looking basically tied there.)
A new Marquette Law School poll finds former Vice President Joe Biden with a 46% to 43% lead over President Donald Trump in Wisconsin, reports CNN. The poll matches the last poll from Marquette, which also had Biden up by 3 points in Wisconsin.
One of the big questions when we look at national polls is whether or not they’re an accurate representation of what is going on at the state level. One of the easiest ways to check is to compare state poll results to the past presidential vote in a given state. I did so for all telephone polls that called cell phones since the beginning of April. When we average out these state polls, they suggest that Biden’s running about 6 points ahead of Hillary Clinton’s final margin.
“In other words, the state level polls suggest that Biden has a national lead of around 8 points.
That’s actually a little greater than the 6.6 points Biden has in the high quality national polling average taken during the same period,” wrote Harry Enten, CNN. “I should note that if we weight the average of state polls to each state’s population, we get a margin just north of that 6.6 point mark. (Weighting by population leaves us somewhat more susceptible to outlier polls, as we have fewer polls from the most populated states.) Either way, all methods agree that Biden has a fairly sizable national advantage.”
Examining the state polls has the advantage of having a lot more data points to play with, so I feel fairly secure that they’re giving us a decent snapshot. We’re looking at more than 20 polls and more than 15,000 interviews. The aggregate margin of error is small.
The presidential race in key states according to early polls
Average margin in states where at least 3 polls were conducted in April
|State||Number of polls||Biden||Trump||Average Margin|
Includes polls conducted partly in March 2020 but finished in April. Polls that released results among multiple populations were included only once, counting the narrowest sample — registered voters over adults, and likely voters over registered voters.
Additionally, we can look at states we expect to be at least somewhat competitive (i.e. those where the margin was within 10 points last time) and those that we don’t think will be close in 2020.
In the competitive states (where most of the state polling has been conducted), there has been an average swing of 6 points toward Biden compared to Clinton’s 2016 result. The same is true in the non-competitive states.
At least from this state level data, it does not seem that either candidate is running up the score disproportionately in areas that were already friendly to him.
We can test our data, too, to see what would happen if the polls are underestimating Trump like they did in 2016.
Biden would still be ahead, even with a 2016 sized mishap. The polls underestimated Trump by 1 point (RealClearPolitics) or 2 points (FiveThirtyEight) in the aggregate of the states we currently have polling from. Applying that 2016 bias to our current data, Biden would have a 6- to 7-point lead nationally.
Biden’s margins in these states are slightly smaller than his advantage in national polls. It’s worth thinking about the race at the state level in these relative terms because there’s still so much time for things to shift. If Biden’s lead nationally narrowed to 2 to 3 percentage points, these states would likely be much closer, if not lean toward Trump. Also, as The New York Times’ Nate Cohn wrote recently, Trump is likely to look stronger when pollsters start limiting their results to “likely voters.” Most of the April surveys in these four states were conducted among registered voters or all adults, two groups that include some people who may not vote in November.4
In other words, this data suggests Trump may have an Electoral College advantage again — he could lose the popular vote and win the election. Of course, this data also suggests that if Biden is winning overall by a margin similar to his advantage now, Trump’s potential Electoral College edge really won’t matter.
Concentrating on just the competitive states, the polls undersold Trump by 2 points (RealClearPolitics) or 3 points (FiveThirtyEight). If the polls in the competitive states were off by as much as they were at the end in 2016, Biden would still be ahead in states like Florida, Michigan and Pennsylvania.
Of course, it may not be wise to expect a 2016-sized polling era in 2020. The polls in these states that had major statewide contests in 2018 were pretty much unbiased. No matter what set of states (all or just competitive) and which aggregate, the polls were not more favorable to Republicans than the final result.
In a state like Wisconsin, the final 2018 Marquette poll nailed the final Senate margin and underestimated the Democratic candidate for governor’s margin by 1 point.
The bottom line is Biden’s ahead right now nationally and in the competitive states. The good news for Trump is he has about six months to change the course of the campaign, which is more than enough time to do so.