A persistent problem for longitudinal studies, particularly those involving human social characteristics and behavior, is the evolution of survey instruments (forms) through the years over which the study is conducted. As the study continues, its organizers may develop a better understanding of the problem domain that necessitates changes to the survey instrument. Even minor presentation changes can significantly impact the collected data. Alternatively, even if the instrument remains fixed, the social and environmental context in which the survey is administered will change.

The Theseus project explores how to streamline the process of integrating data collected under such evolving methodologies. Our core concept is a re-usable encoding of relationships between schemas that can be easily constructed, incrementally maintained, and subsequently queried and analyzed during the variable selection process of a study that uses the resulting data.