John Sides' effort to quantify how polarizing the various candidates are is interesting but, ultimately, quite flawed. "Polarization" is not a quality intrinsic to the various candidates. There is no evidence that, if 10 individuals had dinner with someone perfectly approximating the characteristics and opinions of Hillary Clinton and then 10 individuals had dinner with a working replica of Barack Obama, that there would be any difference in how extreme the dinner guest's reactions would be. Rather, candidates become polarizing as the press, and the political world, polarizes reactions to them. Hillary has been in the public eye for decades, endured all manner of smears and controversies, and is thus quite polarizing. But that's a function of her time before the spotlights, not her personality. As Sides notes, "The candidates with the lowest polarization score were also the candidates with the highest percentage of respondents who couldn’t rate them." Weirdly, though, he goes on to try and compute the scores for these lesser known candidates by assuming "the respondents in each party who could not rate the candidates would come to have preferences with the same ratio of favorable to unfavorable responses to each candidate."
