PolitiFact is a wonderful operation, but like any other analytical tool, it has its limits. The new PunditFact scorecards for the TV networks acknowledge those limits and simultaneously pretend they don’t exist.

Here’s how those contradictory forces play out:

1. Oh, don’t use these scorecards for comparing networks, they say. It’s unfair because CBS has less content than the others and because we aren’t checking every single statement.

2. By the way, CNN is faring the best at 18 percent.

The only way to do well on these scorecards is to come up with questionable things that turn out to be true. If it’s obviously true, PolitiFact won’t (and shouldn’t) bother to check it.

PolitiFact understands that. So why release a number that means nothing?