The attrition of volunteers

We apply a flexible hazard-rate model to analyze the attrition rate of volunteers with the Belgian Red Cross. Our modeling framework handles right-censored and left-filtered observations, incorporates covariates, makes an adjustment for unobserved heterogeneity and estimates the baseline hazard non-parametrically. Two of our findings are of serious concern to the Red Cross administrators. First, the expected length of stay becomes smaller for the more recent entrants. Second, the conditional quitting probability does not decrease, but rather increases, with the volunteer's length of service.