Network executives can seldom resist the opportunity to brag, but sometimes, it’s wiser even if you’re No. 1 by some gee-whiz-sounding barometer to avoid calling attention to it.

In this case, NBC used the introductory portion of its TV Critics Assn. tour presentation Sunday to highlight various ratings accomplishments this season, including the fact its median age had ticked down slightly, to 48.4 (from 49), while CBS (56.4), ABC (53.2) and Fox (45.7) have all gotten older.

After getting sand kicked in its face for so long, the temptation is certainly understandable.

So what’s the problem? There are several.

For starters, most of the reporters/bloggers/dead-people-who-don’t-know-it-yet in the room likely have no idea what median age means or why that would be important. Moreover, other networks are (and once the tidbit hit Twitter, were) quick to point out it really doesn’t mean anything, since networks sell demos based on specific programs, not arbitrary averages.

But the bigger issue is that calling attention to median age just points out how broken the system is, and makes all the networks look like they’re living on borrowed time.

After all, NBC’s tick downward still means half its audience falls at or above the age-49 threshold, when for many advertisers, 18-49 (and for some, 25-54) is their sole objective and thus the end of the line, demo-wise.

HarryslawIn other words, all the major networks — even NBC — skew old, so touting median age is like saying (to quote Jon Stewart) you’re the thinnest kid at fat camp.

Median age also highlights questions of ageism that, for a lot of people, increasingly make less and less sense. OK, so more than half of CBS’ audience is effectively worthless, from a 26-year-old media buyer’s perspective. Is anyone — even younger whippersnappers — supposed to feel good about that, or the fact NBC disappointed a lot of older people by canceling “Harry’s Law” (pictured) just because they didn’t fall inside the hallowed target?

Citing statistics that put the other guys on the defensive before their sessions is fine — hell, it’s entertaining; but using data that makes the whole business model look flawed doesn’t really help anybody. And my guess is rival research departments are working overtime to come up with some way to kick ’em in the ass for it.