Well-defined, informative and cheap indicators are important inany software development organization that needs to evaluateaspects of its development processes and product quality. This isespecially true for large organizations and for organizationsdeveloping complex products; for example automotive safetyfunctions where mechanical, electronic and software systemsneed to interact. In this paper we describe defect backlog profilesas a well-defined, cheap and informative indicator. We definedefect backlog profiles in terms of ISO/IEC 15939, provide atheoretical framework for interpretation, and finally present anevaluation in which we applied the indicator in a longitudinalcase study at an automotive manufacturer. In the case study, wecompare the software integration defect backlog profile for theactive safety component released in 2010 to the profile for thefollowing generation of the same component released in 2015.The results are then linked to a number of process and productchanges that occurred between the two product generations. Weconclude that defect backlog profiles are cheap in terms of datacollection and analysis, and can provide valuable process andproduct quality information although with limitations.