I've taken two Perl certification tests. One was for a former employer who didn't believe in them, but wanted to show them to his customers. The other was for a technical headhunting company, who didn't believe in them but wanted to show them to their customers.

I managed to pass both with flying colors despite the test being just awful. The questions were worded confusingly. Some of the answers on the "best answer" questions were subjectively chosen, and with Perl 4 idioms in mind (this was after 2000). The certification test tend to be no better than the "What do you know about Perl?" articles online (and not as good as the ones from O'Reilly or from The Perl Journal).

So, I'm a certified Perl programmer twice over, at the request of two different companies that had no faith in the certifications. I'm pretty sure Larry Wall, Randal Schwartz, Allison Randal, and Damian Conway haven't bothered. I'm not saying I'm a terrible Perl programmer, but really... wouldn't you rather have one of the other people mentioned writing your code?