Did Medicare's prospective payment system cause length of stay to fall?

It is well accepted that the Medicare Payment System caused average length of stay in United States hospitals to fall, but these calculations have been based on patients in short-stay, acute care hospitals. If one considers all patients covered by Medicare, length of stay rose between 1981 and 1984, although the 1985 value was below the 1981 value. The proximate cause was a marked increase in the proportion of patients staying more than 60 days in the hospital. The data are consistent with a shift of such patients from short-stay, acute care hospitals to other, exempt hospitals and units.