Requirements engineering: The quest for the dependent variable

Requirements engineering is a vibrant and broad research area. It covers a range of activities with different objectives. By reviewing experiments previously included in systematic literature reviews, this paper provides an overview of the dependent variables used in experimental requirements engineering research. This paper also identifies the theoretical motivation for the use of these variables in the experiments. The results show that a wide range of different variables has been applied in experiments and operationalized through both subjective assessments (e.g., subjects´ perceived utility of a technique) and objective measurements (e.g., the number of defects found in a requirements specification). The theoretical basis for these variables and operationalizations are unclear in most cases. Directions for theoretical work to identify suitable dependent variables are provided.