Relationship between utility values and willingness to pay in patients undergoing orthognathic treatment

Objective To determine utility and willingness to pay (WTP) values for pati ents undergoing orthognathic treatment in 3 National Health Service hospita l in the United Kingdom and to establish whether WTP values can be used as a measure of strength of preference. Participants Forty patients who were a bout to start orthognathic treatment were recruited over a 10-month period between January and October 1998. Outcome measures Utility values were obta ined using the standard gamble method and WTP values were determined using a payment card method. The relationship between the two was assessed. Resul ts The mean utility value was 0.73 and the mean WTP was pound6,833. The cor relation between these two measures was -0,46 (P<0.01). Conclusions The cor relation between the utility and WTP values was in the expected direction t hus suggesting that WTP may be used as a measure of strength of preference. Therefore, willingness to pay may be a useful technique to combine with co st utility analysis.