Note, in particular, that there's a high confidence, true, but the claim is "picking language X reduces the chances for bugs by a tiny bit." To quote the abstract:

"It is worth noting that these modest effects arising from language de- sign are overwhelmingly dominated by the process factors such as project size, team size, and commit size. However, we hasten to caution the reader that even these modest effects might quite possibly be due to other, intangible process factors, e.g., the preference of certain personality types for functional, static and strongly typed languages."

Personally I like statically typed languages due to playing nicer with autocompletion and in-editor documentation. Every time people make claims about "upgrades being done when project compiles" I die a little inside.