Static type systems play an essential role in contemporary programming
languages. Despite their importance, whether static type systems influence
human software development capabilities remains an open question. One
frequently mentioned argument for static type systems is that they improve the
maintainability of software systems ? an often used claim for which there is no
empirical evidence. This paper describes an experiment which tests whether
static type systems improve the maintainability of software systems. The
results show rigorous empirical evidence that static type are indeed beneficial
to these activities, except for fixing semantic errors.