If something is going to shake up the race before the Iowa caucuses, it’s likely to be a debate. So we partnered with Ipsos to once again track how Tuesday’s debate, hosted by CNN and The New York Times, affected likely primary voters’ feelings about the candidates. The FiveThirtyEight/Ipsos poll, conducted using Ipsos’s KnowledgePanel, interviewed the same group of voters twice, on either side of the debate, to capture both the “before” and “after” picture.

To better understand which candidates did well or poorly Tuesday night, we plotted how favorably respondents rated the candidates before the debate vs. how debate-watchers rated their performance. And one thing that immediately stands out is that some of the lower-tier candidates did better than we’d expect based on their favorability ratings. Both Pete Buttigieg and Amy Klobuchar were relatively well-liked going in, but got even higher marks for their debate performance than their popularity alone suggests they should. In fact, Buttigieg received the third-highest debate performance grade. Only Bernie Sanders and Elizabeth Warren scored higher, but their debate performances were more in line with their pre-debate favorability ratings. Joe Biden, notably, didn’t have that bad of an overall debate grade, but it was still a bit lower than we might expect given how well-liked he is.

The numbers behind the chart

Candidate Pre-debate favorability Debate performance Elizabeth Warren 71.9% 3.2 Bernie Sanders 66.3 3.1 Pete Buttigieg 64.0 3.1 Joe Biden 68.2 3.0 Amy Klobuchar 54.6 2.9 Kamala Harris 61.2 2.8 Cory Booker 59.4 2.8 Andrew Yang 55.3 2.7 Beto O’Rourke 57.7 2.6 Julián Castro 53.5 2.5 Tom Steyer 48.7 2.5 Tulsi Gabbard 46.7 2.4

In terms of raw debate grades — respondents graded candidates on a four-point scale (higher scores are better) — Warren and Sanders did best, closely followed by Buttigieg, Biden and Klobuchar. Julián Castro, Tom Steyer and Tulsi Gabbard received the worst marks, on average.