Posted by: Gabriele Paolacci | October 7, 2009

Outcome bias

We submitted two scenarios from Baron and Hershey (1988) to a hundred workers (59.0% women, mean age=32.9). Participants were paid $0.05 for a HIT that comprised other unrelated brief tasks. Approximately half of the participants read the following scenario:

A 55-year-old man had a heart condition. He had to stop working because of chest pain. He enjoyed his work and did not want to stop. His pain also interfered with other things, such as travel and recreation. A type of bypass operation would relieve his pain and increase his life expectancy from age 65 to age 70. However, 8% of the people who have this operation die from the operation itself. His physician decided to go ahead with the operation. The operation succeeded.

The other half of participants read an alternative version of the scenario that differed in the outcome: the operation failed and the man died.

All participants evaluated the physician’s decision to go ahead with the operation on a 7-point scale (Stanovich and West 2008): 1= incorrect, a very bad decision; 2 = incorrect, all things considered; 3 = incorrect, but not unreasonable; 4 = the decision and its opposite are equally good; 5 = correct, but the opposite would be reasonable too; 6 = correct, all things considered; 7 = clearly correct, an excellent decision.

Participants who read the positive outcome version evaluated the physician’s decision significantly more favorably than participants who read the negative outcome version, F(1,98)=12.188, MSE=1.863 , p<.001. Therefore the classic outcome bias was displayed.


Baron, J., Hershey, J. C. (1988). Outcome bias in decision evaluation. Journal of Personality and Social Psychology, 54, 569 –579.

Stanovich, K. E., West. R. F. (2008). On the relative independence of thinking biases and cognitive ability. Journal of Personality and Social Psychology, 94, 672-695.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s


%d bloggers like this: