Longitudinal studies are necessary to advance research on health disparities. The reexamination rate of 67.5% in three neighborhoods attests to the successful retention modality we have deployed. This was achieved when we incorporated our unique interim wave, extensive field-based tracking, and the experiences of other researchers into our retention design. The inclusion of medical benefits into the study design motivated individuals who had no access to health care to return and obtain these services. We frequently conducted participant contact information probes, which is an important retention practice in longitudinal studies (Yancey, Ortega, & Kumanyika, 2006). Including monetary compensation for participation may have helped to retain the low-SES cohort who otherwise would be lost to follow-up. Our attrition rate of 15% thus far is comparable to other studies (Gilliss et al., 2001; Kuhns, Vazquez, & Ramirez-Valles, 2008). Thus, to retain participants in this transient and vulnerable population special efforts are essential. While our experience does not provide an exact recipe for successful recruitment and retention, it is clear that direct community involvement by staff and principal investigators and a diverse well trained and culturally competent staff are critical elements.
