Attrition is the bane of any longitudinal study, particularly when it may be nonrandom with respect to key study endpoints. In the TIPS study, attrition at the 10-year follow-up was higher in the usual-detection areas than in the early-detection areas, perhaps because patients in early-detection sites were easier to locate and access because of reduced barriers to participation in health care. Attrition at the 10-year follow-up was also selective, such that more severely impaired patients were overrepresented among those lost from the usual-detection group. Because the loss of more severe cases from usual-detection areas reduces, rather than increases, the likelihood of observing better outcomes among cases from early-detection sites, an attrition artifact cannot explain the finding of higher rates of clinical recovery in cases from early-detection sites, that is, the observed attrition bias only serves to strengthen, rather than diminish, confidence in the primary finding of the study. This selective attrition may, however, help to account for the loss of advantages in favor of early detection on several measures of symptom severity that had been observed in the 2- and 5-year follow-ups.