The study followed 49 undergraduates who had taken Java classes. I would argue that, because of this, the students were probably more experienced with static type systems.
A good point. Also, 49 programmers is very little. But even with thousands of developers using all sorts of languages, it's still moot to draw any conclusion from. It's very subjective and dependant on people's experience/taste/State-of-mind..
For me, switching from static (java) to dynamic typing (common lisp) has saved me a lot of development time. Or did it? Maybe it was Emacs? Maybe it was functional programming? Maybe it was the REPL? Maybe experience?
I think in a lot of cases programmers are happiest with their new hotness simply because they became better and more experienced programmers in the process of learning the new hotness, not because the new hotness is 'good' necessarily.
Using students (especially undergrads) is a typical problem of programmer productivity studies. N=49 and 27h of experimentation time per subject isn't a lot either. Doing a study that can draw actually useful conclusions may just be prohibitievely expensive.
