Why can't we prove the Blub Hypothesis?
ezy: My guess here is that "programmer productivity" is probably the wrong measure.  And that by trying to be reductive about that, you will probably miss somethng valuable...My idea: what if we came up with an app idea and set two teams to it, with the only restriction being the language they could use (one Lisp, one "x").  The "winner" is the one who makes the most compelling app.  Which one is most compelling can be decided in some arbitrary fashion -- My opinion is that it'll be fairly obvious (although I have no idea who would win out!  Just to make that clear :-))This doesn't sound so terribly scientific, does it?  But I think that's about the best you're going to get if you want to measure the effectiveness of a programming language for a chosen task.