US presidential election minus two weeks

This site has cautioned against getting too excited one way or another about movements inside of a percentage point on polling aggregates or of a few points on probability forecasts, such distinctions more than likely to be quite a bit smaller than the ultimate overall polling error. Nonetheless, it presumably means at least something that Donald Trump has gone from slightly behind to slightly ahead in the forecast models of Nate Silver, The Economist and FiveThirtyEight. Going back to my original point though, Silver makes the following observations:

One thing that might be counterintuitive is that even a normal-sized polling error — polls are typically off by around 3 points in one direction or the other — could lead to one candidate sweeping all 7 key battleground states. In our simulations yesterday, which account for the possibility of a correlated polling error, the most common outcome was Trump winning all 7 swing states: this happened 24 percent of the time. And the next most common was a Harris sweep, which occurred in 15 percent of simulations …

The baseline assumption of the Silver Bulletin model is that while the polls could be wrong again — and in fact, they probably will be wrong to some degree — it’s extremely hard to predict the direction of the error. Empirically, there’s basically no correlation in polling error from one cycle to the next one. And pollsters could be overcompensating if they’re worried about missing low on Trump again or if the 2020 polling error was primarily caused by COVID: Democrats being more likely to “socially distance” and having more time to respond to polls. There are prominent examples of this, such as in the 2017 UK election, where pollsters put a heavy finger on the scale for Tories but Labour beat its polls instead.

Adrian Beaumont has more at The Conversation.

Author: William Bowe

William Bowe is a Perth-based election analyst and occasional teacher of political science. His blog, The Poll Bludger, has existed in one form or another since 2004, and is one of the most heavily trafficked websites on Australian politics. View all posts by William Bowe