PT - JOURNAL ARTICLE AU - Kenneth J Winston TI - Performance Measurement Manipulation AID - 10.3905/jpm.2005.500366 DP - 2005 Apr 30 TA - The Journal of Portfolio Management PG - 101--108 VI - 31 IP - 3 4099 - https://pm-research.com/content/31/3/101.short 4100 - https://pm-research.com/content/31/3/101.full AB - Single scalar measures of portfolio performance are inevitably susceptible to manipulation. The Morningstar stars awarded to mutual funds on the basis of huge flows into or out of funds are an example. The system was updated in 2002 and corrects a number of problems with the older system, but—like any single scalar measure—it can be gamed.