The Two-Margin Problem in Insurance Markets.

Area of Science:

• Health Economics
• Insurance Market Dynamics
• Consumer Behavior Analysis

Background:

• Insurance markets exhibit consumer sorting on both extensive (purchase decision) and intensive (plan choice) margins.
• Existing models often analyze these margins separately, limiting a comprehensive understanding of consumer behavior and policy impacts.

Purpose of the Study:

• To develop a unified graphical theoretical framework integrating both extensive and intensive margins of consumer selection in insurance markets.
• To analyze the inherent trade-offs in policies targeting one selection margin on outcomes like prices, enrollment, and welfare.

Main Methods:

• Development of a novel graphical theoretical framework extending standard workhorse models.
• Application of an empirical sufficient statistics approach using data from Massachusetts.
• Linking the empirical analysis directly to the theoretical graphical framework.

Main Results:

• Policies addressing consumer selection on one margin (extensive or intensive) create significant economic trade-offs on the other.
• These trade-offs manifest in changes to insurance prices, enrollment levels, and overall consumer welfare.
• The graphical framework provides a clear visualization of these complex interactions.

Conclusions:

• A simultaneous analysis of both selection margins is crucial for understanding insurance market dynamics.
• Policy interventions require careful consideration of potential unintended consequences on the unaddressed selection margin.
• The developed framework offers a valuable tool for both theoretical analysis and empirical investigation of insurance markets.