"the polls had been fine, more or less[..]. The failure was not so much with the polls but with the people who were analyzing them. [..] The U.S. presidential election [..] was something of a similar case. No, the polls didn’t show a toss-up, as they had in Brexit. But the reporting was much more certain of Clinton’s chances than it should have been based on the polls. Much of The New York Times’s coverage, for instance, implied that Clinton’s odds were close to 100 percent. [..] while a Trump win was unlikely, it should hardly have been unthinkable. [..] It’s hard to reread this coverage without recalling Sean Trende’s essay on “unthinkability bias,” which he wrote in the wake of the Brexit vote. Just as was the case in the U.S. presidential election, voting on the referendum had split strongly along class, education and regional lines, with voters outside of London and without advanced degrees being much more likely to vote to leave the EU. The reporters covering the Brexit campaign, on the other hand, were disproportionately well-educated and principally based in London. They tended to read ambiguous signs — anything from polls to the musings of taxi drivers — as portending a Remain win, and many of them never really processed the idea that Britain could vote to leave the EU until it actually happened. [..] political experts4 aren’t a very diverse group and tend to place a lot of faith in the opinions of other experts and other members of the political establishment. Once a consensus view is established, it tends to reinforce itself until and unless there’s very compelling evidence for the contrary position. Social media, especially Twitter, can amplify the groupthink further. It can be an echo chamber. [..] James Surowiecki’s book “The Wisdom of Crowds” which, despite its name, spends as much time contemplating the shortcomings of such wisdom as it does celebrating its successes. Surowiecki argues5 that crowds usually make good predictions when they satisfy these four conditions: Diversity of opinion. “Each person should have private information, even if it’s just an eccentric interpretation of the known facts.” Independence. “People’s opinions are not determined by the opinions of those around them.” Decentralization. “People are able to specialize and draw on local knowledge.” Aggregation. “Some mechanism exists for turning private judgments into a collective decision.” [..] when he refers to “aggregation,” the broader idea is that there’s some way for individuals to exchange their opinions instead of keeping them to themselves. [..] There was once a notion that whatever challenges the internet created for journalism’s business model, it might at least lead readers to a more geographically and philosophically diverse array of perspectives. But it’s not clear that’s happening, either. Instead, based on data from the news aggregation site Memeorandum, the top news sources (such as the Times, The Washington Post and Politico) have earned progressively more influence over the past decade: The share of total exposure8 for the top five news sources9 climbed from roughly 25 percent a decade ago to around 35 percent last year, and has spiked to above 40 percent so far in 2017. While not a perfect measure10, this is one sign the digital age hasn’t necessarily democratized the news media. Instead, the most notable difference in Memeorandum sources between 2007 and 2017 is the decline of independent blogs; many of the most popular ones from the late ’aughts either folded or (like FiveThirtyEight) were bought by larger news organizations. Thus, blogs and local newspapers — two of the better checks on Northeast Corridor conventional wisdom run amok — have both had less of a say in the conversation."