CASFIS—Approach for studying software product families in industry Mikko Raatikainen, Tomi Männistö, and Timo Soininen Software Business and Engineering Institute (SoberIT) Helsinki University of Technology P.O. Box 9210, FIN-02015 HUT, Finland {Mikko.Raatikainen, Tomi.Mannisto, Timo.Soininen}@hut.fi Abstract. Software product families (SPF) are becoming more commonplace in many industrial organizations due to the increasing variability requirements. One major challenge with SPFs is to understand the challenges companies are facing as well as solutions they have tried out. Feasible tools for gathering such knowledge are qualitative research methods that include the case study method. In this paper, we propose a study framework for SPFs called CASFIS. CASFIS builds on top of case study methodology and existing work and understanding on SPFs with the aim of being a solid framework for investigating industrial SPFs. CASFIS has been tested and tried out in several industrial companies and adjusted accordingly. 1 Introduction A software product family (SPF) is typically understood to roughly consist of common assets that are specifically developed for the SPF and then shared and reused in the de- velopment of the product individuals in the SPF [1] [2] [3]. The concept of a SPF has existed for decades [4], but only recently research results have shown that a SPF may provide industrially relevant benefits, such as decreased development effort and time- to-market [5] [6] and that a SPF itself and some of the issues it addresses are important and predictive for success of reuse [7] [8] [9]. Examples of the success with reuse within SPFs concern various kinds of assets, such as software architecture, instead of only code [3]. Furthermore, reuse is planned and supported instead of opportunistically assumed reuse just happen [2], and reuse is not assumed to be solely a technical problem, but to also concern other issues, such as the business, process, organizational, and archi- tecture (BAPO) concerns [10]. Another important aspect of a SPF in addition to reuse is systematic variability management. Many of the results and issues of SPFs originate from industrial experience including case studies in companies, such as Securitas and Axis [11], CelsiusTech [12] and experience reports in companies, such as Philips [13] and Nokia [14]. In addition to SPFs gaining popularity among researchers, recently, on the one hand, a need for rigorous research methods in software engineering is identified and, on the other hand, software engineering research is required to focus on practical solutions for real problems in the industry [15] [16] [17]. One class of such methods is qualita- tive methods, which include qualitative case study method. Such qualitative methods