Thirty years later: Locating and interviewing participants of the Chicago Longitudinal Study.

Retaining study participants over time is essential for longitudinal studies to prevent selection bias and to achieve their long-term goals. The present paper examines the extent to which participants can be retained in a 30-year longitudinal study when a multi-pronged approach is employed. The paper specifically describes the approach that was used to locate and interview participants of the Chicago Longitudinal Study (CLS), three decades after the study began.