Recent past performance ratings of HMOs predict good performance in the future
Although health plan performance measures remain relatively stable over time, recent past ratings in particular can predict how plans will perform in the future, concludes a new study. Such information about past performance can help consumers make informed decisions about whether or not to enroll in a particular plan, note the study authors. They looked at quality assurance data for six indicators of childhood immunization between 1998 and 2002 from a national database of both publicly and nonpublicly reporting health plans. The researchers used an approach that combined the six indicators into one index of quality and examined the stability of the rankings of this underlying index over time.
Nearly two-thirds of health plans ranking in the upper tier of performance in 1999 continued to maintain such high performance in the following year. Among plans that remained in this upper tier for 2 years in a row (1998 and 1999), nearly three-fourths of them stayed at this level in 2000. The probability of being in the upper tier in 2000 depended on the health plan's state of performance in earlier years. However, ratings from the recent past (2 to 3 years) were more predictive of future performance than ratings from the distant past.
The study also found that performance was not a permanent feature of health plans. More than a quarter of plans deemed upper tier in 1998 and 1999 ceased to remain there in 2000. Health plans that performed well over multiple time periods were most likely to be good performers in the future. The study was supported in part by the Agency for Healthcare Research and Quality (HS10771).
See "Persistence of HMO performance measures," by Shailender Swaminathan, Ph.D., Michael Chernew, Ph.D., and Dennis P. Scanlon, Ph.D., in the December 2008 HSR: Health Services Research 43(6), pp. 2033-2049.
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