William Ackman Needs Sharper Ideas in ADP Questbr Pershing Square contends the stock could double within four years through changed management incentives, betterbr integration of operations, streamlining of the business and greater emphasis on software development.br The harshest comment, however, was the nearly 5 percent drop in his target’s share price during Mr. Ackman’s presentation, which may explain why he said toward the end of the three-hour callbr that the company probably needed a new chief executive.br Since building his stake, Mr. Ackman has been called “dead wrong” by Leon Cooperman, a fellow hedge fund titanbr and former ADP board member, and a “spoiled brat” by Carlos Rodriguez, ADP’s chief executive.br Mr. Ackman says he “knows that people respond to incentives,” so he thinks that taking off caps on executive compensation will unleash performance.br Growing rivals like Workday and Ultimate Software offer cloud-based servicesbr that tend to be cheaper, faster to set up and more convenient than incumbent firms.