Willingness to Pay: A Valid and Reliable Measure of Health State Preference?

Med Decis Making. Jul-Sep 1994;14(3):289-97. doi: 10.1177/0272989X9401400311.


The development of methods to measure willingness to pay (WTP) has renewed interest in cost-benefit analysis (CBA) for the economic evaluation of health care programs. The authors studied the construct validity and test-retest reliability of WTP as a measure of health state preferences in a survey of 102 persons (mean age 62 years; 54% male) who had chronic lung disease (forced expiratory volume < 70%). Interview measurements included self-reported symptoms, the oxygen-cost diagram for dyspnea, Short-Form 36 for general health status, rating scale and standard gamble for value and utility of current health state relative to death and healthy lung functioning, and WTP for a hypothetical intervention offering a 99% chance of healthy lung functioning and a 1% chance of death. WTP was elicited by a simple bidding game. To test for starting-point bias, the respondents were randomly assigned to one of five starting bids. All health status and preference measurements except WTP (controlling for income) showed significant (p < 0.05) difference between disease-severity groups (mild/moderate/severe). WTP was significantly (p = 0.01) associated with household income, but other health status and preference measure were not. The measure most highly correlated with WTP was standard gamble (r = -0.46). There was no association between starting bid and mean WTP adjusted for income and health status. The test-retest reliability of WTP was acceptable (r = 0.66) but lower than that for the standard gamble (r = 0.82).(ABSTRACT TRUNCATED AT 250 WORDS)

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Analysis of Variance
  • Attitude to Health*
  • Cost-Benefit Analysis / methods*
  • Female
  • Financing, Personal* / statistics & numerical data
  • Health Status
  • Humans
  • Income
  • Lung Diseases, Obstructive / diagnosis
  • Lung Diseases, Obstructive / economics
  • Lung Diseases, Obstructive / therapy
  • Male
  • Middle Aged
  • Ontario
  • Quality of Life
  • Reproducibility of Results
  • Severity of Illness Index
  • Surveys and Questionnaires
  • Value of Life*