Software product lines are used in companies to provide a set of reusable assets for related groups of software products. Generally a software product line provides a common architecture and reusable code for software product developers. In this article we focus on mechanisms that help developers vary the architecture and behavior of a software product line to create individual products. We provide the reader with a framework of terminology and concepts that help understand the concept of variability better. In addition, we present a number of variability mechanisms in the context of this framework. Finally, we provide a method for incorporating variability into software product lines.

Rapporten diskuterar variabilitet i produktlinjer, dvs förmågan att förändra produktlinjen för de individuella produkterna i produktlinjen. Utgångspunkten är från grupperingar av krav, s.k. features. I rapporten presenteras även en taxonomi över tillgängliga variabilitetsmekanismer.