A Steep Hill to Climb

The Harris Poll that came out today is getting a lot of attention; Harris’s headline says that 50% of U.S. adults would not vote for Hillary Clinton if she ran for President.
A huge caveat, though, is in order: while the poll’s sample size was quite large, over 2,000, it was an online poll in which people apparently answered demographic questions about themselves, and then responded to a series of questions about Hillary Clinton. Online polls in general are unreliable. Harris tried to correct for the main biases inherent in online polling by weighting for the obvious demographic factors (age, gender, income level, etc.) and adding “[p]ropensity score weighting … to adjust for respondents