FiveThirtyEight partnered with Morning Consult to ask likely voters, “Who do you think won?” In order to get an idea of which candidates gained (or lost) support as a result of their debate performances, they asked likely voters who they would vote for before and after each debate. This enabled them to determine where that support came from (or went to). Their results provide a snapshot of where the candidates stood going into the first debate, their position the next morning and where they finished the morning after the second debate.

The results showed that Kamala Harris was the biggest winner from the first round of debates. Elizabeth Warren saw a modest increase in support. Bernie Sanders and Cory Booker performed somewhat well in their debates, although they did not receive significant increases in support.

Julian Castro increased his support by 1%. But, because he went into the debate with 0.7% support, a one point increase was significant. The most surprising development for Castro, however, was the 18.5% increase in his favorability rating, the greatest jump of any candidate in the field.

Joe Biden was the biggest loser.

Here are some of the significant changes by candidate:

 

Kamala Harris: Gain: 8.7%

Before first debate: 7.9%

After first debate: 6.3%

After second debate: 16.6%

Change in Favorability: +10.7%

Change in Unfavorability: +1.5%

According to FiveThirtyEight statistics, the increase in Harris’ support came from Joe Biden and Elizabeth Warren.

 

Elizabeth Warren: Gain: 1.8%

Before first debate: 12.6%

After first debate: 18%

After second debate: 14.4%

Change in Favorability: +1%

Change in Unfavorability: -1%

 

Bernie Sanders: Gain 2.9%

Before first debate: 14.4%

After first debate: 16.4%

After second debate: 17.3%

Change in Favorability: +2%

Change in Unfavorability: -0.1%

 

Julian Castro: Gain 1%

Before first debate: 0.7%

After first debate: 2.1%

After second debate: 1.7%

Change in Favorability: +18.5%

Change in Unfavorability: +2.4%

 

Joe Biden: Loss: 10%

Before first debate: 41.5%

After first debate: 35.4%

After second debate: 31.5%

Change in Favorability: -1%

Change in Unfavorability: +3%

 

Pete Buttigieg: Loss: 1.9%

Before first debate: 6.7%

After first debate: 4.4%

After second debate: 4.8%

Change in Favorability: +9.4%

Change in Unfavorability: +3.8%

 

Corey Booker: Loss: 0.2%

Before first debate: 3%

After first debate: 3.9%

After second debate: 2.8%

Change in Favorability: +9.9%

Change in Unfavorability: +1.9%

 

Beto O’Rourke: Loss: 1.4%

Before first debate: 3.6%

After first debate: 2.8%

After second debate: 2.2%

Change in Favorability: +2.4%

Change in Unfavorability: +6.7%

 

Many of the lesser known candidates saw an 8-10% increase in their favorability ratings. Included in this group are Corey Booker, Amy Klobuchar, Kamala Harris, Pete Buttigieg, Kirsten Gillibrand, Eric Swalwell, Bill deBlasio, Tim Ryan, Tulsi Gabbard, Jay Inslee, John Delaney, Andrew Yang, John Hickenlooper, Michael Bennet and Marianne Williamson.

Julian Castro, as mentioned above, increased his favorability by a whopping 18.5%, the largest jump of any of the candidates.

Marianne Williamson increased her unfavorability by 16.6%. Next was Andrew Yang by 11%. Eric Swalwell and Michael Bennet each increased their unfavorability by 10.2%, John Hickenlooper by 9.8%, John Delaney by 8.6% and others by lesser amounts.

I agree with comedian and talk show host Bill Maher’s assessment that half of the field should bow out at this point. This would include former Colorado Gov. John Hickenlooper, Colorado Sen. Michael Bennet, former Maryland Rep. John Delaney, Ohio Rep. Tim Ryan, New York Sen. Kirsten Gillibrand, California Rep. Eric Swalwell, spiritual guru Marianne Williamson, tech entrepreneur Andrew Yang, former Texas Rep. Beto O’Rourke, and New York City Mayor Bill de Blasio. My colleague, Alex Parker, posted about this last night here.

I would include Rep. Tulsi Gabbard (D-HI) in that list, and probably Maher would too, but she happened to be a guest on his program when he was discussing the list.

 

Note: Full FiveThirtyEight survey results can be viewed here.