Research suggests that racial and ethnic minorities are more likely to attrit from longitudinal trauma studies than non-Hispanic Whites. Yet, little is known about how the loss of minority participants influences longitudinal findings as well as internal and external validity of study findings. Thus, the present study examined the effects of race/ethnicity on attrition in a longitudinal trauma study of women (minority = 223, non-Hispanic White or majority = 459) exposed to a campus shooting. Survival analyses were used to compare the attrition rates of minority participants to majority participants and assess the extent to which race/ethnicity, among other variables, predicted attrition. Minority participants were more likely to attrit than majority participants, hazard ratio (HR) = 0.69, 95% CI [0.48, 0.99], even after adjusting for study variables. A main effect was also found for age, HR = 1.06, 95% CI [1.01, 1.12]. Race/ethnicity did not interact with other study variables to influence attrition. The findings underscored the importance of assessing the effects of attrition on longitudinal findings and external validity.
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