"Harry Potter" author J.K. Rowling has made it clear that she thinks Donald Trump is worse than her villain Voldemort, so she would probably be glad to hear her readers think so too. A new study from a University of Pennsylvania professor found that those who have read about the famous boy wizard have an unfavorable view of the Republican presidential nominee. It only gets worse for The Donald because opinions drop even more if people have read all seven books. The study, "Harry Potter and the Deathly Donald," was written by Diana Mutz, a professor of political science and communication. It will appear in a special 2016 election issue of "PS: Political Science and Politics." Mutz polled a nationally representative sample of 1,142 Americans in 2014 and again in 2016 and asked them, among other things, to rank their feelings toward Trump on a 0 to 100 scale. The study found that each "Harry Potter" book read lowered participants' thoughts on Trump by about two to three points. The study noted that party affiliation did not affect whether a person had read the "Harry Potter" novels. "Because Trump's political views are widely viewed as opposed to the values espoused in the 'Harry Potter' series, exposure to the Potter series may play an influential role in influencing how Americans respond to Donald Trump," Mutz wrote in the study. For example, Harry Potter and his cohorts are against the enslavement of house elves and privilege given to pure blood wizards, while Trump has made comments that some minority groups find racist and offensive. The study also collected data about the "Harry Potter" movies but said they do not predict opinions on Trump. It's not clear why not, but the study speculates it may be because Republicans were less likely to watch the films than Democrats, and because the books delve more into characters' dispositions than the movies. "Throughout the series, love and kindness consistently triumph over aggression and prejudice. It's a powerful positive theme, and thus not surprising that readers understand the underlying message of this storyline, and are moved by it," Mutz said. "Harry Potter's popularity worldwide stands to make a difference not just in the U.S. election, but in elections across Europe that involve aggressive and domineering candidates worldwide."