A new Texas Lyceum poll gives Donald Trump a six point lead over Hillary Clinton among likely voters in a head-head match-up. That's pretty much in line with other recent Texas polls. What caught our attention is that among all registered voters, it is Clinton with a four point lead. That's a 10 point difference.

Most pollsters use a likely voter screen in the weeks leading up to the election, and that's what we use in our tables, when both are available. However, defining likely voters is a challenge for pollsters, as this 2012 article discusses.

Perhaps this kind of difference reflects more passion for one candidate. At the same time, it could highlight an opportunity if one candidate's 'get out the vote' effort can significantly outperform on Election Day.