“With a team of researchers including my University of Pennsylvania colleague Diana Mutz and the University of Massachusetts’ Seth Goldman, I’ve been conducting the Institute for the Study of Citizens and Politics panel, a survey which has asked the same respondents questions about politics over almost nine years. So we know what our respondents thought, both in January/February 2016, just before and after the Iowa caucuses, and in mid-October, when our last wave of the survey was fielded. [...]

When asked about a matchup among Clinton, Trump and other candidates2, a significant majority of the respondents gave the same answer both in both months: 37.2 percent backed Clinton both times, 30.9 percent backed Trump both times, and 12.7 percent opted for another candidate or said they wouldn’t vote both times. In all, that means that around 80.7 percent of respondents gave the same answer in both surveys.”