Strategies and costs of building and maintaining a longitudinal disaster cohort

Long-term individual recovery from a catastrophic event involves the restoration of critical lifelines such as housing and employment as well as social and emotional well-being, particularly for displaced and highly traumatized populations. One strategy for measuring recovery over time involves a longitudinal observational cohort. This analysis examines the cost and effort involved in developing and maintaining a longitudinal cohort. The Gulf Coast Child and Family Health Study recruited 1,079 randomly sampled individuals in Louisiana and Mississippi within months after Hurricane Katrina and followed them for 13 years. Participants in the study were interviewed in person five times over the study period. Despite the challenges involved in maintaining a transient and economically vulnerable study cohort, 80.4 percent of all eligible participants were surveyed at the fifth time point, over a decade after the event. At each round of data collection, the refusal rate ranged from less than 1 percent to 3.3 percent. Reasons for non-participation included institutional inaccessibility for those who were incarcerated, in treatment programs, or in nursing homes. Physical and mental health issues which precluded participation included cognitive decline and significant loss of function. Other participants were lost to follow-up or death. At the final round of face-to-face interviewing in 2018, the average field cost per survey was $353.27, not including a respondent incentive of $50, and required an average of 15.74 hours per case to complete. This report describes the strategies employed to maintain such a long-term disaster cohort.