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Psychology of Patient Sections
Author Bio
Introduction
Omission Bias
Discount Rates
Framing
Assessing Probabilities
Currently selected section: Predicting Utility
Sequences
Role-based decisions
Role of Emotions
Visceral Influences
Conclusion
Chapter 4: The Psychology of Patient Decision Making: Predicting Utility
        

As was the case with estimating probabilities accurately, assessing the desirability or utility of various outcomes is also essential for good decision making.  Choosing wisely among options is impossible if one’s evaluation of an option is inaccurate.  To demonstrate the evaluation of outcomes consider Brickman, Coates, and Janoff-Buhlman (1978).

Seeing the results, most people are surprised to learn that the newly rich lottery winners rated their happiness at this stage of their life as only 4.0, which does not differ significantly from the rating of the control subjects.  Also surprising to many people is the fact that the paraplegics and quadriplegics rated their lives at 3.0, which is above the midpoint of the scale (2.5).

To the extent that people cannot predict the utility of unknown states of health, to that extent they are unable to make decisions which are “in their own best interest.”  The ratings given by the control subjects, the accident victims, and the lottery winners pertain to their “experienced utility,” which is their opinion of the state they are actually experiencing at the current time (Kahneman and Snell, 1992).  However, decisions are often made before all possible outcome states are experienced.  Therefore one can only predict what the experienced utility will be like.  If the prediction is in error, then a decision contrary to one’s best interests may occur.  For example, if people knew that winning a huge prize in a state lottery would cause only an insignificant change in their happiness, then many people would cease buying lottery tickets.

As individuals face important medical decisions, the outcome states might be quite unfamiliar. The choice between radiation or surgery for prostate cancer might hinge on one’s appreciation of the outcome states following the selection of each option. Can laypersons with absolutely no experience with the outcome states be expected to make an adequate appraisal of each of them? Much research suggests that they cannot. For example, Boyd et al., (1990) solicited the utility of life with a colostomy from several different groups: patients who had rectal cancer and who had been treated by radiation, patients who had rectal cancer and who had been treated by a colostomy, physicians who had experience treating patients with gastrointestinal malignancies, and two groups of healthy individuals. The patients with a colostomy and the physicians rated life with a colostomy significantly higher than did the other three groups. Similarly, Sackett and Torrance (1978) found that those on dialysis rated their state of health higher than did members of the general public who predicted how they would rate their state of health if they were on dialysis.  However other researchers have found that people can make relatively accurate predictions concerning the utility of impending health states (e.g. Llewellyn-Thomas, Sutherland, and Thiel, 1993; Rachman and Eyrl, 1989).  To the extent that persons cannot predict what being in a future health state would be like, it will be extremely difficult for them to make decisions in their own best interest.  Interactive videos and other educational programs have been developed to try to inform patients what living with particular outcomes would be like (e.g. Barry et al., 1995; Liao et al., 1996).  Whether such programs will enable patients to rate such health states the same as those already in the health state is unknown.  It is also unknown whether patients should rate such health states the same as those already in the state.  Individual differences exist, and we should not expect all patients to rate the same health state in the same way.  What is needed for good decision making, however, is that the patient be able to predict what the experienced utility will be. This is often an unrealized expectation.

Note that the inability to appreciate the utility of future health states also has important implications for “informed consent.”  If a patient facing a medical decision does not assign the same utilities to various possible outcome states that a typical person in each health state assigns, to what extent is the patient sufficiently well informed to make the decision? Can that person render decisions in his or her own best interest? Can we blame patients who do not?

 

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