To compare patients' and physicians' perceptions of the value of a medical service, such as cord-blood stem cell banking, whose future benefits are ambiguous, and to investigate if the differences in perceptions derive from discrepant assessments of the probability of realizing benefits, of the magnitude of benefits, or both. Also, to investigate if the differences in perceptions depend on whether the service offers unambiguous benefits in addition to ambiguous benefits.
Four hundred thirty-nine 18-45 years old U.S. women (“patients”) and 59 U.S. obstetric providers (“physicians”) were asked to predict benefits (probability and magnitude) of cord-blood stem cell banking within the next 5, 10, 20 and 40 years. Patients were then randomly assigned to 1 of 3 scenarios representing varying degrees of ambiguity about the benefits – (A) only unambiguous benefits, (B) both unambiguous and ambiguous benefits, or (C) only ambiguous benefits – and reported their family's willingness to pay for the service. Physicians were also asked to predict a typical family's willingness to pay in each scenario.
Patients' predictions of the probability of realizing benefits are significantly more favorable than physicians' (16%, 26%, 39% and 52% versus 2%, 4%, 7% and 12% at 5, 10, 20 and 40 years respectively; p < 0.001 for all). See Figure 1. Predictions of magnitude of benefits, in contrast, were not significantly different at 5, 10 and 20 years, but were significantly more favorable among patients at 40 years (p < 0.01).
Physicians underestimated families' willingness to pay in all scenarios for families with income < $50K (p < 0.05) but not for families with income $50-100K. Interestingly, a service offering both unambiguous and ambiguous benefits has significantly lower value than a service with only unambiguous benefits to families with income $50-100K (p < 0.05), but not to physicians or to families with income < $50K.
Patients and physicians have different perceptions of the value of a medical service with ambiguous future benefits, owing primarily to different perceptions of the probability of realizing the benefits. Physicians underestimated willingness to pay for a service in low-income families. These differences suggest the value of improved communication between physicians and patients when the benefits of a medical service are ambiguous.