Polls may understate Trump support

Donald Trump leads the GOP presidential field in polls of Republican voters nationally and in most early voting states, but some polls may actually be understating his support, according to a new study.

The analysis, by Morning Consult, a polling and market research company, looked at an odd occurrence that has cropped up repeatedly this year: Trump generally does better in online polls than in surveys done by phone.

Morning Consult ran an experiment: It polled 2,397 potential Republican voters earlier this month using three different methods — a traditional telephone survey with live interviewers calling land lines and cellphones, an online survey, and an interactive dialing technique that calls people by telephone and asks them to respond to recorded questions by hitting buttons on their phone.

The experiment confirmed that "voters are about six points more likely to support Trump when they're taking the poll online than when they're talking to a live interviewer," said Morning Consult's polling director, Kyle Dropp.

The most telling part of the experiment, however, was that not all types of people responded the same way. Among blue-collar Republicans, who have formed the core of Trump's support, the polls were about the same regardless of method. But among college-educated Republicans, a bigger difference appeared, with Trump scoring 9 points better in the online poll. Social-desirability bias — the tendency of people to hesitate to confess certain unpopular views to a pollster — provides the most likely explanation

Tribune Washington Bureau