The discussion of the party identification composition of poll samples comes up in every presidential election with which I’ve been involved.
Interested observers often opine that when a given poll shows that Candidate X is ahead, it cannot be correct because there is a higher percentage of voters who identify with Candidate X’s party in the sample than there should be, based on comparison to some previous standard.
There are several reasons why this is a faulty approach to evaluating a poll’s results. [cont.]
Frank Newport, Gallup