We regard a software system as consisting not only of its source code, but also of its documented models. Traceability is defined as the ability to trace the dependent items within a model and the ability to trace the correspondent items in other models. A common use of the term traceability is requirements traceability which is the ability to trace a requirement via the different models to its implementation in the source code. Traceability is regarded as a quality factor that facilitates maintenance of a software system.

The thesis is the result from a case study performed on a large commercial software system developed with an object-oriented methodology and largely implemented in C++ and by using a relational database. A number of concrete traceability examples collected from the project are the result of a thorough investigation of the various models that were produced during the project. The exemples are thoroughly analyzed and discussed, forming the main contribution of this research. Insight and knowledge as regards traceability and object­ oriented modeling is the result from the work with the examples.