Objectives
To test whether consumer inertia in choosing primary care clinics (PCCs) in a tiered total cost of care system can be reduced by supplying tailored information on clinic cost directly to consumers during open enrollment.
Study Design
Randomized controlled trial among individuals with employment-based health insurance. Members were randomly assigned by their zip code of residence, with 100 zip codes assigned to the treatment group and 100 to the control group.
Methods
During the open enrollment period for calendar year 2020, members in the treatment group received emails providing enhanced tier information on the most popular PCCs in their zip code. We ran regression analyses to evaluate the marginal effect of the targeted intervention on consumer choice.
Results
The intervention had only a small marginal effect on choice of PCC. Before the intervention, nearly 85% of consumers were selecting PCCs in the 2 tiers with the lowest cost sharing, suggesting that tiering alone may already have addressed the problems of poor information and distorted prices inherent in many health insurance designs.
Conclusions
Providing members with enhanced tier information on local PCCs had a limited marginal effect on consumer choice, suggesting that informational interventions alone are insufficient to overcome existing inertia or, potentially, that consumers were already adequately informed through the tiered total cost of care benefit design.

