A study published by the Journal of the American Medical Association shows a large decline in BPCI participation. Of the hospitals who were eligible to enroll in bundled payments, only 12 percent actually participated in the program. Of that group almost half did not continue participating. The program is voluntary and is structured around episodes of care which are 30, 60, and 90 days in length. Participants can realize a gain if certain cost targets met. The main difficultly is that in markets where there are many low cost competitors, there are little opportunities to move the cost downward. This is because the target price of the bundle is in part based on the market in which the hospital is in. A lower starting index means it will be very difficult to achieve savings and ultimately realize a gain.