Just seven candidates qualified for Thursday’s debate, making it the smallest face-off yet, and we once again partnered with Ipsos to track how the debate, hosted by “PBS NewsHour” and Politico, affected likely primary voters’ feelings about the candidates on the stage. The FiveThirtyEight/Ipsos poll, conducted using Ipsos’s KnowledgePanel, interviewed the same group of voters twice, once on either side of the debate, to capture both the “before” and “after” picture.

To better understand which candidates did well or poorly Thursday night, we plotted how favorably respondents rated the candidates before the debate vs. how debate-watchers rated candidates’ performances afterward. And if it’s hard to see a breakout star in this round, that’s because Joe Biden, Elizabeth Warren and Bernie Sanders are clustered very close together. Although Biden received the highest marks, his high pre-debate favorability rating means we expected a lot of voters to be predisposed to viewing his debate performance in a positive light. It is notable, though, that Biden received high marks, as he hasn’t fared nearly as well in some of our other post-debate surveys. Warren and Sanders were tied for a close second place in their debate grade, but, like with Biden, their pre-debate favorability ratings meant we figured voters would rate them positively — Warren was even slightly worse than expected. Andrew Yang and Amy Klobuchar, on the other hand, did better than expected given their pre-debate favorability ratings, earning the third-highest marks. Being the focus of several of his rivals’ attacks seems to have hurt Pete Buttigeg; he got low marks relative to how well-liked he was going into the debate. Tom Steyer also failed to make a positive impression.

The numbers behind the chart

Candidate Pre-debate favorability Debate performance Joe Biden 66.3% 3.2 Bernie Sanders 65.1 3.1 Elizabeth Warren 64.8 3.1 Andrew Yang 55.5 3.0 Amy Klobuchar 54.3 3.0 Pete Buttigieg 62.5 2.9 Tom Steyer 50.4 2.7

In terms of raw debate grades — respondents graded candidates on a four-point scale (higher scores are better) — Biden got the highest average score, closely followed by Sanders and Warren, who tied for second; Yang and Klobuchar also did well.