“…Incentive effects of linear contracts have also been analyzed in various empirical studies. Many of these investigations reveal a positive correlation between monetary rewards and effort (see, e.g., Bailey, Brown, and Cocco 1998;Lazear 2000;Sprinkle 2000), whereas others do not find any positive effects (Bonner, Hastie, Sprinkle, and Young 2000;Jenkins, Mitra, Gupta, and Shaw 1998). A positive relationship between rewards and effort is also reported in experimental analyses of contractual relationships (e.g., Riedl 1993, 1998), though the evidence suggests that its degree is quite sensitive to the institutional setting (e.g., Van der Heijden, Nelissen, Potters, and Verbon 2001;Charness, Frechette, and Kagel 2004).…”