Each barb had echoes of what the two wonks told TPM in recent emails.
The latest round began with Krugman linking to what he described as the "definitive piece on what's wrong, so far, with the new FiveThirtyEight."
"For all the big talk about data-driven analysis,what it actually delivers is sloppy and casual opining with a bit of data used, as the old saying goes, the way a drunkard uses a lamppost — for support, not illumination," Krugman wrote in what was his fourth post on Silver since the new site launched earlier this month.
But as he has in his other negative reviews of FiveThirtyEight, Krugman expressed hope that Silver and company will turn things around. Similarly, Krugman told TPM in an email on Sunday that he's been a "Nate fan," but that he "expected more thoughtfulness" at the new FiveThirtyEight.
Silver responded on Wednesday evening with a snark-laden post. He mocked the New York Times' headline construction ("For Columnist, a Change of Tone") and used a table to show that Krugman's negative view of FiveThirtyEight coincided with Silver's move to ESPN.
The table included all 33 references (neutral, favorable or unfavorable) to Silver and FiveThirtyEight in Krugman's blog dating back to 2008.
Silver wrote that Krugman "has mentioned FiveThirtyEight four times in just nine days, all in negative contexts" and noted that he's "frequently criticized what he calls 'pundits' and 'opinion journalists,' including those who write for The Times."
That's why he told TPM in an email on Monday that he wasn't caught off guard by Krugman's criticism.
"I haven't been surprised by Krugman's criticism because I've fired some shots at the New York Times editorial page, of which he's a member," Silver said. "Krugman was full of praise for FiveThirtyEight while it was part of The New York Times."
Silver closed his latest retort by cheekily observing that, at his current pace, Krugman "will write 425 more blog posts about FiveThirtyEight between now and the 2016 presidential election."