Abstract
The authors have held both academic and industrial research positions, and have designed and carried out many empirical studies of large software systems that were built and maintained in industrial environments. Their experiences show that the most crucial component of a successful study is the participation of at least one industrial collaborator who is committed to the study's goals and is able to provide advice and assistance throughout the course of the study. This paper describes studies carried out in three different industrial environments, discusses obstacles that arise, and how the authors have been able to overcome some of those obstacles.