The defect escape rate is a metric that assesses the collective quality of software releases by evaluating how often errors are discovered and rectified in the pre-production process versus during production. The defect escape rate is a KPI (Key Performance Indicator) that measures how many defects are found in released code versus how many are found during development. This KPI can help you to compare how much time is spent troubleshooting issues found during development versus how much time is spent troubleshooting issues found in released code. The higher the defect escape rate, the more defects are found in released code, and thus more time is spent troubleshooting issues in released code.