Studying the evolution and enhancement of software features

The evolution and enhancement of features during system evolution can have significant effects on its coherence as well as its internal architecture. Studying the evolution of system features and concepts across a product line from an external or problem domain perspective can inform the process of identifying and designing future features. We show how we derive three primary views (morphological, functional, and an object view), from the user-level structures and operations of a system, using a case study of Microsoft Word's evolution. We show how these views illustrate feature evolution over three versions of Word. Lastly, we discuss the lessons learned from our study of feature evolution.