The two scientific polls after the second 2016 presidential debate showed a Clinton win, but a more marginal one than after the first debate.

Judged as of 11 October 2016. True if the two scientific instant polls of debate watchers released after the 9 October 2016 second presidential debate (e.g. CNN/ORC and YouGov) both found more respondents judged Clinton the winner, and the margins in those polls were clearly smaller than the margins Clinton recorded in the comparable scientific polls after the first debate (26 September 2016). Mostly true if both showed a Clinton win and the margins were smaller overall but one poll's drop was slight, or if there was a third scientific poll alongside the two. Mixed if only one of the two showed a Clinton win, or both showed a win but only one showed a smaller margin than after the first debate. Mostly false if both showed a Clinton win but margins were similar to or larger than after the first debate. False if the scientific polls showed Trump winning or a tie.

Set before the research began.

1. E1 Clinton wins, Trump exceeds expectations, but few move | CNN Politics CNN · 10 October 2016

   “Among voters who watched the debate, 57% said Clinton did the best job in the face-off at Washington University in St. Louis, while just 34% thought Trump did.”

2. E2 Clinton wins, Trump exceeds expectations, but few move | CNN Politics CNN · 10 October 2016

   “That’s a less commanding victory for Clinton than in the first debate, but she still boosted her edge over Trump among debate watchers on handling the economy and being the stronger leader.”

3. E3 Clinton beats Trump 47% to 42% in second Presidential debate YouGov · 10 October 2016

   “According to YouGov's post-debate poll, which interviewed 812 registered voters who watched the debate, Hillary Clinton won the debate against Donald Trump by 47% to 42%.”

4. E4 Putting post-debate 'flash polls' into perspective Pew Research Center · 17 October 2016

   “In one such CNN/ORC poll conducted after the first presidential debate on Sept. 26, Clinton was called the winner over Trump by a margin of 62%-27%.”

After the second debate, both scientific instant polls found Clinton the winner: CNN/ORC had her ahead 57% to 34% (E1) and YouGov had her ahead 47% to 42% (E3). For CNN/ORC, the 23-point margin is clearly smaller than its 62%-27% (35-point) result after the first debate (E4), and CNN itself called the win "less commanding" (E2). The evidence gives no YouGov first-debate figure, so the smaller margin is confirmed for only one of the two polls, although YouGov's 5-point margin is itself narrow. The claim is largely supported but not fully confirmed under the criteria.