Beyond productivity in software maintenance: factors affecting lead time in servicing users´ requests

Research on the economics of software maintenance has concentrated on software maintenance productivity. More often than not, maintenance productivity is measured by the number of hours spent in servicing a maintenance request. While this measure captures the cost of an information systems (IS) department, it ignores a potential opportunity cost to the users that is better captured by the lead time taken to fulfil a request. Using detailed data of more than 1000 maintenance projects collected at a field site over a 6-year period, we examine how the lead time of a request is affected by factors such as the characteristics of the system, the request, and the maintainer responsible for the request. We found that the complexity of a request significantly postpones its lead time. The lead time is also increased by the internal lead time target set by the IS department based on staff availability. We also divided the lead time into the queuing time and the service time components and study how they are influenced by the same factors