The percentage of merged pull requests that address defects.
We determine that a PR is addressing a defect by looking at its title and looking for the presence of a set of keywords, specifically any word that begins with:
Thus, it will match things like "reverts", "bugfix", "fixes", "repairs" etc. Because we're looking for words that begin with these keywords, we'll match for "fixes", but not "prefix".
Defect Rate is only calculated for merged PRs.
Defect Rate only analyzes PR titles, and not commit messages or branch names.