Why do data journalists keep missing the political story of the year?

[Commentary] Four months ago, after Donald Trump built a surprise lead in national (and some state) polls, I asked the most prominent political "data journalists" if they were eating crow yet. Nate Cohn, a reporter for the New York Times's Upshot, admitted his "surprise" that Trump had not yet eroded. Nate Silver, the founder and editor of FiveThirtyEight, was somewhat less retrospective, pointing to evidence that the media was overrating Trump. "It seems like you’re being pretty straw-manny and cherry-picky," wrote Silver. Well, it's December, and good luck reaching into the tree and plucking anything but cherries.

When I wrote that piece, Trump was averaging 23.8 percent in national polls. In a CNN poll released Dec 4, Trump is at 36 percent. When that poll is added to the invaluable RealClearPolitics average, Trump is at 30.8 percent. For five months, Trump has been able to swing into states and draw the biggest crowds of any Republican candidate. It's been two and a half months since a thinly-attended South Carolina event, organized by a third party group, that was supposed to mark the end of Trumpmania. It's been a month since a rambling Trump speech in Iowa, where even the people standing behind him grew bored with his rants about Ben Carson. The crowds kept coming. And they keep coming.