Critical Decline?

In perusing back issues of econ journals I’ve always enjoyed the critical commentary sections.  Today, however, commentary is less frequent.  Writing in the latest issue of Econ Journal Watch, Coelho, De Worken-Elly III, and MCClure present some hard data on the decline.  The Quarterly Journal of Economics, for example, used to prints lots of short commentary pieces but now hardly prints any.

The authors decry the decline but don’t explain it.

One explanation is that the opportunity cost of space at the top journals has increased.  One hundred years ago the top journals were (more or less) the AER, JPE, and QJE, all among the top journals today.  One hundred years ago the journals published about the same amount of material as they do today.  Yet the number of economists today is many times that of one hundred years ago.  Since more articles are competing for the same number of printed pages it follows that on the intensive margin average article quality will increase and on the extensive margin types of articles with lower value will decline.  Since comments are on average of less value than original contributions it’s not surprising that they have declined over time.

At the same time as commentary has declined in the top journals, the total number of journals has increased so it’s not obvious that total commentary has declined.  Indeed, don’t we now have EJW?