Adverse Selection When Buyers Have More Information: The Market for Insurance

Adverse selection occurs when buyers with more knowledge about their own risk purchase insurance at premiums based on average risk. High-risk individuals, aware of their elevated likelihood of filing claims, are more inclined to purchase insurance than low-risk individuals. This creates a skewed risk pool dominated by high-risk buyers, raising overall costs for insurers and driving premiums higher for everyone.

Low-risk individuals perceive premiums based on average risk as disproportionately high relative to their actual risk level. Since the premium reflects the average of both high-risk and low-risk buyers, low-risk individuals with low-risk lifestyles or excellent health find the cost unjustifiable. They choose not to purchase, leaving a pool dominated by high-risk individuals.

Asymmetric information means insurance companies lack detailed insights into individual risk levels of clients. When insurers cannot distinguish between high-risk and low-risk buyers, they set premiums based on average risk. This information gap allows high-risk buyers to purchase at favorable rates while low-risk buyers exit the market, creating adverse selection.

High-risk individuals are most likely to purchase insurance, including those in hazardous occupations like logging, construction, or offshore oil drilling, those with high-risk hobbies such as skydiving or rock climbing, and people with pre-existing medical conditions or risky health behaviors. These groups recognize their increased likelihood of benefiting from coverage.

As low-risk individuals exit the market due to high premiums, the remaining pool becomes increasingly dominated by high-risk individuals. This raises the overall cost for insurers, forcing them to increase premiums further. This cycle threatens the affordability and accessibility of insurance for all participants, potentially destabilizing the entire market.

Sarah, a logging worker, knows she has a higher probability of injury from harsh weather and remote work conditions. She purchases insurance at the average premium, which is affordable for her high risk. However, Mary, an office support staff member with lower injury risk, finds the same premium too expensive and declines coverage, leaving a pool skewed toward high-risk individuals like Sarah.

Adverse selection arises when products of differing quality are sold at a uniform price due to asymmetric information. Insurance companies charge one premium rate despite knowing clients have different risk levels. This uniform pricing attracts high-risk buyers who benefit most and repels low-risk buyers who overpay, creating an imbalanced risk pool.