Depends on what you mean by type errors. For example, NPEs in Java are technically a "type error", in that your code is mishandling data due to insufficiently s

Depends on what you mean by type errors. For example, NPEs in Java are technically a "type error", in that your code is mishandling data due to insufficiently specified types, and I'd have no trouble believing that 15% of Java bugs are NPEs or otherwise null-related. If you extend the definition of type errors to include nulling issues, I'd have no trouble believing that TS reduces the bug rate by that much or more, since TypeScript lets you have non-nullable types. Of course, you could argue that Java devs are just as lacking in quality and experience as JS/TS devs, but that starts to sound suspiciously like No True Scotsman/"real programmers do it in x86 assembly".