title: Conjoint analysis versus rating and ranking for values elicitation and clarification in colorectal cancer screening.
abstract: OBJECTIVE
  To compare two techniques for eliciting and clarifying patient values for decision making about colorectal cancer (CRC) screening: choice-based conjoint analysis and a rating and ranking task.
  
  
  METHODS
  Using our decision lab registry and university e-mail lists, we recruited average risk adults ages 48-75 for a written, mailed survey. Eligible participants were given basic information about CRC screening and six attributes of CRC screening tests, then randomized to complete either a choice-based conjoint analysis with 16 discrete choice tasks or a rating and ranking task. The main outcome was the most important attribute, as determined from conjoint analysis or participant ranking. Conjoint analysis-based most important attribute was determined from individual patient-level utilities generated using multinomial logistic regression and hierarchical Bayesian modeling.
  
  
  RESULTS
  Of the 114 eligible participants, 104 completed and returned questionnaires. Mean age was 57 (range 48-73), 70% were female, 88% were white, 71% were college graduates, and 62% were up to date with CRC screening. Ability to reduce CRC incidence and mortality was the most frequent most important attribute for both the conjoint analysis (56% of respondents) and rating/ranking (76% of respondents) groups, and these proportions differed significantly between groups (absolute difference 20%, 95% CI 3%, 37%, p =0.03). There were no significant differences between groups in proportion with clear values (p = 0.352), intent to be screened (p = 0.226) or unlabelled test preference (p = 0.521)
  
  
  CONCLUSIONS
  Choice-based conjoint analysis produced somewhat different patterns of attribute importance than a rating and ranking task, but had little effect on other outcomes.
authors.affiliation: Department of Medicine, Cecil Sheps Center for Health Services Research and Lineberger Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA. pignone@med.unc.edu
authors.forename: Michael P
authors.initials: MP
authors.lastname: Pignone
authors.forename: Alison T
authors.initials: AT
authors.lastname: Brenner
authors.forename: Sarah
authors.initials: S
authors.lastname: Hawley
authors.forename: Stacey L
authors.initials: SL
authors.lastname: Sheridan
authors.forename: Carmen L
authors.initials: CL
authors.lastname: Lewis
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Jonas
authors.forename: Kirsten
authors.initials: K
authors.lastname: Howard
mesh_terms: D000368:Aged; D001294:Attitude to Health; D001499:Bayes Theorem; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology*; D003625:Data Collection / Q000379:methods; D003657:Decision Making; D055088:Early Detection of Cancer / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged