title: Specification of the utility function in discrete choice experiments.
abstract: BACKGROUND
  The specification of the utility function has received limited attention within the discrete choice experiment (DCE) literature. This lack of investigation is surprising given that evidence from the contingent valuation literature suggests that welfare estimates are sensitive to different specifications of the utility function.
  
  
  OBJECTIVE
  This study investigates the effect of different specifications of the utility function on results within a DCE.
  
  
  METHODS
  The DCE elicited the public's preferences for waiting time for hip and knee replacement and estimated willingness to wait (WTW).
  
  
  RESULTS
  The results showed that the WTW for the different patient profiles varied considerably across the three different specifications of the utility function. Assuming a linear utility function led to much higher estimates of marginal rates of substitution (WTWs) than with nonlinear specifications. The goodness-of-fit measures indicated that nonlinear specifications were superior.
authors.affiliation: Health Economics Research Unit, University of Aberdeen, Abedeen, UK. Electronic address: m.vanderpol@abdn.ac.uk.
authors.forename: Marjon
authors.initials: M
authors.lastname: van der Pol
authors.affiliation: University of Calgary, Calgary, AB, Canada.
authors.forename: Gillian
authors.initials: G
authors.lastname: Currie
authors.affiliation: University of Toronto, Toronto, ON, Canada.
authors.forename: Seija
authors.initials: S
authors.lastname: Kromm
authors.affiliation: Health Economics Research Unit, University of Aberdeen, Abedeen, UK.
authors.forename: Mandy
authors.initials: M
authors.lastname: Ryan
mesh_terms: D019644:Arthroplasty, Replacement, Hip / Q000379:methods; D019645:Arthroplasty, Replacement, Knee / Q000379:methods; D002755:Choice Behavior; D017144:Focus Groups; D006801:Humans; D016014:Linear Models; D008962:Models, Theoretical; D017711:Nonlinear Dynamics; D057240:Patient Preference; D010865:Pilot Projects; D011795:Surveys and Questionnaires; D013997:Time Factors; D014850:Waiting Lists
keywords: discrete choice experiments; specification of utility function