Abstract
Abstract: The task of finding an optimal selection of requirements for the next release of a software system is difficult as requirements may depend on each other in complex ways. This paper presents the results from an in-depth study of the interdependencies within 5 distinct sets of requirements, each including 20 high-priority requirements of 5 distinct products from 5 different companies. The results show that (1) roughly 20% of the requirements are responsible for 75% of the interdependencies, (2) only a few requirements are singular, (3) customer-specific bespoke development tend to include more functionality-related dependencies whereas market-driven product development have an emphasis on value-related dependencies. Several strategies for reducing the effort needed for identifying and managing interdependecies are outlined. A technique for visualization of interdependecies with the aim of supporting release planning is also discussed. The complexity of requirements inter-dependency analysis is studied in relation to metrics of requirements coupling. Finally, a number of issues for further research are identified.