Defect density is a metric that measures the number of defects relative to the size of the software component (e.g., per thousand lines of code). It is particularly useful for evaluating the effectiveness of the peer review process in removing defects. By calculating defect density before and after the peer review process, teams can assess how many defects were identified and addressed during reviews. This metric helps in understanding the quality of the code and the effectiveness of the review process in identifying and mitigating defects. Higher effectiveness in peer reviews typically results in lower defect density. Industry practices and standards, such as those from IEEE or ISO, often recommend using defect density as a key quality metric.