Nate Silver writes that groupthink contributed to the media's inability to foresee the 2016 results.
For starters, American newsrooms are not very diverse along racial or gender lines, and it’s not clear the situation is improving much.6 And in a country where educational attainment is an increasingly important predictor of cultural and political behavior, some 92 percent of journalists have college degrees. A degree didn’t used to be a de facto prerequisite7 for a reporting job; just 70 percent of journalists had college degrees in 1982 and only 58 percent did in 1971.
The political diversity of journalists is not very strong, either. As of 2013, only 7 percent of them identified as Republicans (although only 28 percent called themselves Democrats with the majority saying they were independents). And although it’s not a perfect approximation — in most newsrooms, the people who issue endorsements are not the same as the ones who do reporting — there’s reason to think that the industry was particularly out of sync with Trump. Of the major newspapers that endorsed either Clinton or Trump, only 3 percent (2 of 59) endorsed Trump. By comparison, 46 percent of newspapers to endorse either Barack Obama or Mitt Romney endorsed Romney in 2012. Furthermore, as the media has become less representative of right-of-center views — and as conservatives have rebelled against the political establishment — there’s been an increasing and perhaps self-reinforcing cleavage between conservative news and opinion outlets such as Breitbart and the rest of the media.
Although it’s harder to measure, I’d also argue that there’s a lack of diversity when it comes to skill sets and methods of thinking in political journalism. Publications such as Buzzfeed or (the now defunct) Gawker.com get a lot of shade from traditional journalists when they do things that challenge conventional journalistic paradigms. But a lot of traditional journalistic practices are done by rote or out of habit, such as routinely granting anonymity to staffers to discuss campaign strategy even when there isn’t much journalistic merit in it. Meanwhile, speaking from personal experience, I’ve found the reception of “data journalists” by traditional journalists to be unfriendly, although there have been exceptions.