Preferred Pharmacy Networks and Drug Costs

Working Paper: NBER ID: w24862

Authors: Amanda Starc; Ashley Swanson

Abstract: Selective contracting is an increasingly popular tool for reducing health care costs, but these savings must be weighed against consumer surplus losses from restricted access. In both public and private prescription drug insurance plans, issuers utilize preferred pharmacy networks to reduce drug prices. We show that, in the Medicare Part D program, drug plans with more restrictive preferred pharmacy networks, and plans with fewer enrollees who are insensitive to preferred pharmacy discounts on copays, pay lower retail drug prices. We then use estimates of plan and pharmacy demand to estimate the first-order costs and benefits of selective contracting in the presence of enrollees with heterogeneous sensitivity to preferred supplier incentives.

Keywords: Medicare Part D; pharmacy networks; drug pricing

JEL Codes: I13; L1


Causal Claims Network Graph

Edges that are evidenced by causal inference methods are in orange, and the rest are in light blue.


Causal Claims

CauseEffect
restrictive pharmacy networks (L42)lower retail drug prices (L42)
higher percentage of LIS enrollees (I13)limited savings from steering (D61)
higher percentage of LIS enrollees (I13)increase in drug prices (E31)

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