A practice by insurers of selling policies only to people who do not need medical care; then dropping them once they do. Any Medicare provider paid under a risk (capitated) plan, for instance, has an incentive to pursue this form of favorable selection. Some efforts to do this are illegal (such as asking Medicare HMO enrollees about their health status prior to joining), but it is apparently not illegal for HMO’s to have their offices up one flight of stairs to discourage some potential enrollees, or to affirmatively market the HMO plan in environments frequented by the healthier retirees.