Outcome bias in ethical judgment : replication and extension

Abstract

Outcome bias refers to the phenomenon that people tend to to judge the quality of decisions based on the outcome it brought. In a pre-registered study with an American online Amazon Mechanical Turk sample (N = 402), we conducted a very close replication of Experiment 1 from Gino, Moore, and Bazerman (2009). The original study found outcome bias affected moral judgment (η2 = .059, 95%CI [.004, .16]), and our replication supports these findings (η2 = .04, 95%CI [.03, .12]). We extended the replication by adding a neutral condition without specifying the outcome. We found that people rated a decision as more unethical when outcome was negative than when there was no outcome specified (d = 0.81, 95%CI [0.55, 1.05], p < .001). Lastly, we found that outcome bias weakens when decision-makers do not have “inside knowledge” regarding the chances of outcomes being positive or negative. Our results suggest that outcome bias in ethical judgment depends on inside knowledge (η2 =.35, 95%CI[.54, .66]). outcome bias in ethicality was even stronger when decision-makers had no inside knowledge.