title: A comparison of two approaches for assessing patient importance weights to conduct an Extended Q-TWiST analysis.
abstract: OBJECTIVE
  Patient-centered methods for evaluating treatments require validated preference-elicitation techniques. We describe the validation of two preference-elicitation approaches for use in an Extended Q-TWiST treatment evaluation. The first method was an "idiographic" approach, which attempts to capture intra-individual differences in the degree to which each domain distracted from and interfered with life activities. The second method, a Likert-scaled approach, asks patients to evaluate the importance of each quality-of-life (QOL) domain.
  
  
  METHODS
  Patient-reported QOL and preferences were assessed in participants with gastroesophageal reflux disease at baseline (n = 172), one week (n = 25), and 4 weeks after baseline (n = 100).
  
  
  RESULTS
  Both approaches demonstrated high internal consistency and the ability to discriminate known groups based on reported pain and number of days with symptoms. The idiographic approach exhibited responsiveness, although it was more highly correlated with QOL than the Likert-scaled approach. The Likert-scaled approach had good face validity but demonstrated low reliability compared to the idiographic approach.
  
  
  CONCLUSIONS
  Both preference-elicitation methods exhibited promise as well as limitations. Future research should focus on increasing the reliability of the Likert-scaled approach, reducing the overlap between the idiographic approach and QOL, and examining the relationship between reliability and responsiveness for a range of illness trajectories.
authors.affiliation: Behavioral Science Research Program, Frontier Science & Technology Research Foundation, Inc., Chestnut Hill, MA, USA. schwartz@jimmy.harvard.edu
authors.forename: C E
authors.initials: CE
authors.lastname: Schwartz
authors.forename: S D
authors.initials: SD
authors.lastname: Mathias
authors.forename: D J
authors.initials: DJ
authors.lastname: Pasta
authors.forename: H H
authors.initials: HH
authors.lastname: Colwell
authors.forename: B D
authors.initials: BD
authors.lastname: Rapkin
authors.forename: M W
authors.initials: MW
authors.lastname: Genderson
authors.forename: J M
authors.initials: JM
authors.lastname: Henning
mesh_terms: D000203:Activities of Daily Living; D003657:Decision Making; D005260:Female; D005500:Follow-Up Studies; D005764:Gastroesophageal Reflux / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D011594:Psychometrics / Q000379:methods*; D011788:Quality of Life; D015203:Reproducibility of Results; D014481:United States