People who are the most at risk for health problems are the most likely to sign up for health insurance. Health insurance premiu
ms rise to cover the increased costs of these people, whereupon the less at risk drop their health insurance coverage, worsening the problem. This problem is called the
Adverse selection problem happens when sicker people, or people with a higher risk to the insurer buy health insurance while healthier or less risk people don't buy it.
This selection problem puts the insurer at a higher risk of losing money through claims than he had predicted.