[crdoconnor]

My experience is that having a really great design eliminates a lot of bugs (60% is perhaps not unreasonable, although pretty hard to measure), but having an awesome design is not even close to being the same thing as doing regular code reviews.

I'm often thrown in to a project with bad to mediocre design and I am not able to just change the design to become "good" just by reviewing PRs. I can only attempt to push the design into a slightly better direction over a long period of time.

Similarly, just because it's reviewed doesn't mean that the design is great.

I am probably able to hit something approaching 45% defect detection rate with integration testing on most projects though.

With code reviews I'd say it's about 1 or 2%. Bug-wise, I usually only spot fairly obvious "language" gotchas (e.g. initializing an empty list in a method signature in python).