Berger, ThorstenThorstenBergerLettner, DanielaDanielaLettnerRubin, JuliaJuliaRubinGrünbacher, PaulPaulGrünbacherSilva, Adeline de SousaAdeline de SousaSilvaBecker, MartinMartinBeckerChechik, MarshaMarshaChechikCzarnecki, KrzysztofKrzysztofCzarnecki2022-03-122022-03-122015https://publica.fraunhofer.de/handle/publica/38991210.1145/2791060.27911082-s2.0-84982822069The notion of features is commonly used to describe the functional and non-functional characteristics of a system. In software product line engineering, features often become the prime entities of software reuse and are used to distinguish the individual products of a product line. Properly decomposing a product line into features, and correctly using features in all engineering phases, is core to the immediate and long-term success of such a system. Yet, although more than ten different definitions of the term feature exist, it is still a very abstract concept. Definitions lack concrete guidelines on how to use the notion of features in practice. To address this gap, we present a qualitative empirical study on actual feature usage in industry. Our study covers three large companies and an in-depth, contextualized analysis of 23 features, perceived by the interviewees as typical, atypical (outlier), good, or bad representatives of features. Using structured interviews, we investigate the rationales that lead to a feature's perception, and identify and analyze core characteristics (facets) of these features. Among others, we find that good features precisely describe customer-relevant functionality, while bad features primarily arise from rashly executed processes. Outlier features, serving unusual purposes, are necessary, but do not require the full engineering process of typical features.ensoftware product lineproduct line engineeringfeatureconference paper