Yesterday I linked to a piece by Robert A. Book that argues that the administrative cost advantage claimed for Medicare vanishes when the cost is computed properly.
Greg Mankiw then linked to the piece (giving me credit and a link--thanks, Greg!).
Then Paul Krugman linked to Mankiw and claimed that Book's argument was really wrong.
Book then replied--I think effectively--to Krugman's argument.
Then Columbia professor Andrew Gelman praised in part and criticized in part Book's piece.
Book replied to him, too. (Again, I think effectively.)
There are days when this blogging/real-time Internet thing is very cool.