The effect of price on switching among health plans.

A recent policy change by the University of California (UC) provides a unique natural experiment for investigating the sensitivity of consumers to health plan premiums. When the UC moved to a policy of limiting its contribution to the cost of the least expensive plan, out-of-pocket premiums increased for roughly one-third of UC employees. We examine the extent to which UC employees switched plans in response to this change in premiums. Our results indicate a strong response. Individuals facing premium increases of less than $10 were roughly 5 times as likely to switch plans as those whose premiums remained constant.