Quick answer: Bug resolution count doesn't equal resolution quality. Re-opened bug rate, customer-satisfaction post-resolution, and re-occurrence in patches surface quality.
Closing a bug isn't the same as fixing it. Track the quality.
Re-opened rate
Bugs re-opened within 30 days. High rate = closures aren't quality.
Customer post-survey
'Your bug was fixed; how is it now?' Quick survey; reveals partial fixes.
Re-occurrence in patches
Same bug re-appears? Track. Pattern surfaces.
Per-engineer quality
Resolution count + quality. Recognized; recalibrates expectations.
“Quality of fix matters as much as quantity. Track both.”
If your studio measures closures only, the quality is silent. Add the quality dimension.