esting represents a crucial activity to ensure software health. Previous studies showed that test-related factors (e.g., code coverage) can predict the future software code quality, as measured by post-release defects. These studies provided compelling evidence on the relation between tests and postrelease defects, yet they considered different test-related factors separately: as such, there is still a lack of knowledge of whether these factors are still good predictors when considering all together. In this talk proposal, we report the results of a recent study we conducted on how test-related factors relate to production code quality in APACHE systems. We investigated how the presence of tests relates to post-release defects; then, we analyzed the role played by the test-related factors previously shown as significantly related to post-release defects. From the practitioner’s perspective, the findings of the study show that, when controlling for other metrics (e.g., size), test-related factors have a limited connection to post-release defects.