Huselid and Becker (1995) have found that there are greater gains from adopting HPWP at both the low and high end of the performance distribution but not so much in the middle. Using various measures of an HR system they find a seven to nine per cent effect on market value for a narrow measure of HPWPs, and 11-13 per cent for a broader measure, when either is changed by one standard deviation. Based on average employment costs these effects are equivalent, they suggest, to a cash value of from $38,000 to $73,000. They suggest that achieving such benefits takes some time and effort.