Information and drug prices: evidence from the Medicare discount drug card program

In early 2004, the U.S. Government initiated the Medicare Discount Drug Card Program (MDDCP), which created a market for drug cards that allowed elderly and handicapped subscribers to obtain discounts on their prescription drug purchases. Pharmacy-level prices for many drugs were posted on the program website weekly from May 29, 2004 to December 31, 2005, as the largest undertaking in the history of government-sponsored information release began with the hope of promoting competition by facilitating access to prices. A large panel of pharmacy-level drug price data collected from the Medicare website indicates that there was significant and persistent dispersion in prices across cards throughout the program. Moreover, the time-path of prices was non-monotonic; the prices declined initially when consumers were choosing cards but rose later when subscribers were unable to switch from one card to another. In contrast, contemporaneous control prices from on-line drug retailers, which were unrelated to the program, rose steadily over time, indicating that MDDCP prices evolved in a way different from the general evolution of prices outside the program. In view of the fact that the program rules prevented consumers from changing their cards at will, the evolution of MDDCP prices is consistent with certain models of dynamic price competition with consumer switching costs, such as Klemperer?s (1987a,b). Estimates of potential savings from purchasing at program prices are also provided.