AP
He proposed a "put up or shut up" type of bet with MSNBC's Joe Scarborough (earning a rebuke from the NYT's own public editor).
So why did he do it?
During a Q&A session on Reddit, he was asked about his conflicts with other pundits:
Be honest. How much did you enjoy getting the ire of pundits (not the few who actually critiqued your method, models, or assumptions, but those who just dismissed your work wholesale)? Was there a part of you that wrung your hands together, laughed a tad manically, and egged them on to continue, since all they were doing was bringing more attention to your work and the lack of rigor in their approach?
His answer? These disputes were a way for him to get more out of his confidence that the election was won:
At some point in the last few weeks of the election, I guess I decided to lean into the upside outcome a little bit in terms of pushing back at the pundits in my public appearances -- as opposed to emphasizing the uncertainty in the model, as I had for most of the year. (Nothing about the model design itself changed -- just how I tended to talk about it.) Stupid poker analogy: part of playing well is in maximizing the amount of value you get from a hand in the event that things go well, in addition to mitigating your losses if they don't.
When you see a big opportunity, you better do all you can to exploit it right then.