Physicians' sick-listing practices have been studied to a very limited extent. There is limited scientific evidence that physicians perceive sick-listing duties to be difficult and problematic, regarding both the medical and the insurance-related aspects. There is limited scientific evidence also that quality is often deficient in the sickness certificates issued by physicians. This may affect case management at the local insurance office. There is insufficient scientific evidence to explain the differences in physicians' sick-listing patterns. The effects on patients are also insufficiently studied.