EFFECTS OF DECISION AMBIGUITY AND CONFLICTS OF INTEREST ON PERCEIVED VALUE OF A MEDICAL SERVICE

Purpose: To evaluate effects of decision ambiguity and physician conflict of interest (COI) on willingness to pay (WTP) for cord-blood stem cell banking (SCB), a service with ambiguous future benefits.

Methods: 439 U.S. women 18-45 years old were randomly assigned to 1 of 3 scenarios representing varying degrees of ambiguity about the future benefits of cord-blood stem cell banking: (A) only unambiguous benefits (1/2500 probability of a benefit), (B) both unambiguous and ambiguous benefits, or (C) only ambiguous benefits. Participants were stratified by annual income (<$50K, $50-100K), producing 6 groups (3 scenarios, 2 income categories).  Participants were asked for their WTP for the service.  Then they were asked again for WTP after being told that their obstetrician recommends the service to her family and also has financial relationships with the company providing the service. Participants were also asked how much (0-10) they trust their obstetrician to make the decision for their family and who should make the decision, both before and after the conflicts of interest were disclosed.

Results: Before subjects were given information about COI, mean WTP within the 6 groups ranged from $480 (lower income, ambiguous benefits) to $2255 (higher income, unambiguous benefits). In both income strata mean WTP was significantly (p<0.05) higher in Scenario A (without ambiguity) than in Scenario C (ambiguity only) (Figure 1).  Higher income ($50K-$100K) subjects had significantly (p<0.05) lower WTP in Scenario B (unambiguous and ambiguous benefits) compared to Scenario A (unambiguous only), but this anomalous result was not found among lower income subjects.  As expected women with higher incomes had higher mean WTP than lower income subjects in Scenarios A and C, but unexpectedly not in Scenario B.    Disclosure of physician COI reduced WTP by 19-53% in all scenarios and both income strata, but the reduction was significant (p<0.05) only in Scenario C, in which the future health benefits are ambiguous. Trust in having their obstetrician make the decision for their family and willingness to share the decision were both reduced significantly in all scenarios after the conflicts of interest were disclosed.

Conclusions: Ambiguity in future health benefits reduces the perceived value of a medical service. Conflicts of interest reduce perceived value more when benefits are ambiguous than when they are unambiguous.