In this presentation, we will summarize the evolving story of our work with various longitudinal data series for secondary research, DDI-Lifecycle, and Colectica tools like Designer and the Portal. 

The aging archive within ICPSR, the National Archive of Computerized Data on Aging (NACDA), preserves and shares data collections to serve the research community. ICPSR has been a long-time user of DDI, specifically DDI-Codebook, which allows secondary data users to review variable-level items directly from the ICPSR websites. The ICPSR variable view has worked well for providing data discovery within a single data collection or data series. 

NACDA hosts many data collections that have two or more collection timepoints. To provide secondary data users with an effective way to view the research potential across these longitudinal series, we have been working with DDI-Lifecycle and a Colectica Portal. The NACDA Colectica Portal facilitates the exploration of data across multiple timepoints in a single research series, and across more than one research series. We will outline some history of our trials, errors, and solutions, as well as practical examples from the research collections for which we have created concordances.