I come from a fairly strong OO background, the benefits of OOD & OOP are second nature to me, but recently I\'ve found myself in a development shop tied to a procedural prog
I doubt you will find a definitive study. As several people have mentioned this is not a reproducible experiment. You will find anecdotal evidence, a lot of it. Some people may find some statistical studies, but I would examine them carefully. I am not aware of any really good ones.
I also will make another point, there is no such thing as purely object oriented or purely procedural in the real world. Many if not most object methods are written with procedural code. At the same time many procedural programs use OO methodologies such as encapsulation (also call abstraction by some).
Don't get me wrong, OO and procedural programs look and are different, but it is a matter of dark gray vs light gray instead of black and white.