Measuring patient preferences by willingness to pay to avoid: the case of acute otitis media

The aim of this study was to evaluate willingness to pay (WTP) to avoid as a method of eliciting relative values for use in expected-value (EV) decision making. Parents' preferences for the events and outcomes associated with acute otitis media (AOM) and its treatment were quantified by means of a questionnaire asking how much they would be willing to pay to avoid them. Their responses were then used to calculate the EVs of treating or not treating presumed AOM with antibiotics. The advantages of the WTP method were its simplicity, its analogy with everyday financial transactions, its explicit recognition of illness and its management as involving decreases in value, and its face validity. The disadvantages included the need to use another method (the standard gamble) to derive a value for death and the wide ranges and the poor test-retest reliability of individual parents' responses. Nonetheless, median WTP values and their ranges may prove useful in defining for physicians and policymakers the parameters of their practical management decisions. In the case of AOM, the EV of treating with antibiotics was, for the aggregate sample and for most individual parents, robustly superior because of parents' desire to avoid any increased risk of their children's death.