Traceability analysis is crucial to the development of web-centric systems, particularly those with frequent system changes, fine-grained evolution and maintenance, and high level of requirements uncertainty. A trace model at the level of the web system architecture is presented in this paper to address the specific challenges of developing web-centric systems. The trace model separates the concerns of different stakeholders in the web development life cycle into viewpoints; and classifies each viewpoint into structure and behaviour. Tracing relationships are presented along two dimensions: within viewpoints; and among viewpoints. Examples of tracing relationships are presented using UML. This trace model is demonstrated through its application to the design of a commercial web project using a web-design process. The design artifacts in each activity are transformed based on the artifacts tracing relationship in the trace model. The model provides mechanisms for verification of consistency, completeness and coverage within each viewpoint and the connectedness across viewpoints
