The problem of attracting members who are sicker than the general population, specifically, members who are sicker than was anticipated when developing the budget for medical costs. A tendency for utilization of health services in a population group to be higher than average or the tendency for a person who is in poor health to be enrolled in a health plan where he or she is below the average risk of the group. From an insurance perspective, adverse selection occurs when persons with poorer-than-average health status apply for, or continue, insurance coverage to a greater extent than do persons with average or better health expectations. Occurs when premium doesn’t cover cost. Some populations, perhaps due to age or health status, have a great potential for high utilization. Some population parameter such as age (e.g., a much greater number of 65-year-olds or older to young population) that increases the potential for higher utilization and often increases costs above those covered by a payers capitation rate. Among applicants for a given group or individual program, the tendency for those with an impaired health status, or who are prone to higher than average utilization of benefits, to be enrolled in disproportionate numbers and lower deductible plans.