We decided to offer some participants the opportunity to earn a relatively small bonus (equivalent to about one day’s pay at their regular pay rate). Others would have a chance to earn a medium-sized bonus (equivalent to about two weeks’ pay at their regular rate). The fortunate few, and the most important group for our purposes, could earn a very large bonus, equal to about five months of their regular pay. By comparing the performances of these three groups, we hoped to get a better idea of how effective the bonuses were in improving performance.
