This sounds good, but it will not work for many jobs. Fixing a bug in a code base that you don't recognize is more difficult that a well defined coding problem.

This sounds good, but it will not work for many jobs. Fixing a bug in a code base that you don't recognize is more difficult that a well defined coding problem. Candidates will be limited to the technologies and problems which they are already familiar. This approach has some value, but it can't be the only way to evaluate candidates.