Our retention strategy mirrored the recruitment strategy in that we sought to maintain and further develop communication channels with community residents, local governmental officials as well as to maintain competent staff invested in the research enterprise. The strategy consisted of frequent contact information validity probes, an interim evaluation, and data collection wave, conducting study impact focus groups, maintaining community advisory board contacts, implementing field-based tracking and tracing, developing electronic tracking and tracing protocols, and mail and telephone contact protocols. We used a variety of techniques to update contact information, including a periodic newsletter mailing (The Healthy Journey, see http://handls.nih.gov/05Part-04News.htm) and holiday and birthday cards. The high volume of undeliverable mail made it crucial to devise a method to track this transient population using direct methods. The study protocol was initially designed to revisit the cohort after four years, but we introduced an interim study (Wave 2 Interim Follow-up Study) that contacted participants 1.5 years after their initial examination. The interim study was an unusual retention strategy that served multiple purposes by administering the Revised NEO Personality Inventory, testing telephone methods
