I think it's unfair to criticise the lack of studies for that specific question without acknowledging that there are exceedingly few studies that show a benefit for static typing despite the fact that a huge number of people feel that there must be an effect.
IIRC there was a study that looked at the proportion of Github issues labeled as bugs, by language. Clojure came in with the lowest proportion. I overall prefer static typing, depending on what I'm doing, but I think avoiding ubiquitous mutable state is a lot more important than typing.
