And as you can see in the table below, the first debate not only saw the most movement in the polls — 2.4 points, on average — but it also saw the biggest drop or gain for any of the candidates. After that first debate, Harris gained 8.3 points and Biden lost 6.5 points.
Compared to the first debate, though, the last three debates just haven’t corresponded with as big of a move in the polls — about a one-point difference, on average. So there is evidence that the Democratic contest has, in fact, been pretty stable so far, or at the very least, the debates haven’t dramatically shaken up the race. But that got me thinking, is what we’re seeing in 2020 all that different from any other cycle?