Bosses who use performance rankings to pit employees against one another so they will work harder are actually creating the opposite effect, according to a study. "Workers can become complacent and demotivated," said Iwan Barankay, a management professor at the Wharton School of the University of Pennsylvania. "People who rank highly think, 'I am already No. 1, so why try harder?' And people who are far behind can become depressed about their work and give up."