Are elders better scientists?

A recent paper, discussed in a recent issue of Nature, found that across disciplines, professors in their 50s and 60s published about twice the number of papers each year as professors in their 30s. This is taken in the article as evidence that older professors can be very productive.

Nature allows readers to common on news briefs, and the comments raised the same issues I had. Here are the first two, for instance:

They don't seem to consider that older professors have larger research groups, i.e. more underlings to actually write the papers. Perhaps a better photo to illustrate the story would be the aged professor in their office wielding a red pen over their students' manuscripts.

Well, the older professors are also more established and have more connections, and therefore can participate in both small and large collaborative projects. No offense, but this survey only seems to prove an already obvious point.

Basically, older faculty tend to not only have more graduate students and post-docs, they also tend to have broad collaboration networks. This is not to say that older researchers are not productive, or that even less-productive older researchers aren't valuable members of the community, just that these data seem hard to interpret.