Donald Trump falls behind in the USC/L.A. Times poll, one of his favorites

Among Donald Trump’s favorite polls this election season is the USC/LA Times Daybreak tracking poll because it so often has shown him ahead when most other polls reported he was behind.

But Trump is unlikely to cite the poll on Twitter or during any of his campaign events Wednesday. For the first time since early September, even the USC/LA Times poll has Hillary Clinton leading.

The poll often is out of sync with other voter surveys because it uses different methodology. It asks voters to estimate, on a scale of 0 to 100, how likely they are to vote for a particular candidate and crunches the results for a daily forecast.

Using the same technique, the poll predicted President Obama’s margin of victory within half a percentage point in 2012.

But the daily poll results often do not immediately reflect voter attitude shifts following a major event, like the release of a video last week in which Trump boasted of sexually assaulting women. That’s because the voters who participate are given a week to respond to each round of questions, and each day’s results reflect an average of the previous week’s responses. There generally is a nine-day lag before major opinion shifts emerge in the result.

Being a polling outlier has invited no small measure of criticism in this contentious election year. But some, including star pollster Nate Silver of Five Thirty Eight, say “Leave the L.A. Times Poll Alone,” cautioning that it provides useful data and that pollster “herding” — shifting results to match what others are finding — is a terrible habit for the profession.

And the results, as they were for much of Trump’s run in the lead, remain within the margin of error.

Have more questions about the USC/Los Angeles Times tracking poll? Find answers here.