title: What underlies the perception that a medical intervention is effective? An exploratory study among smokers.
abstract: BACKGROUND
  The perceived ineffectiveness of medical interventions is a key predictor of their underuse. This study explores the nature of this perception with regards to a range of medical interventions.
  
  
  METHODS
  Adult smokers (n = 18) completed interviews and questionnaires using the repertory grid technique to elicit personal constructs underlying perceptions of effectiveness of a range of medical interventions (three to stop smoking, three to prevent heart disease, one to reduce pain, one to lose weight, and one to treat depression). Principle components analysis was applied to identify the key underlying dimensions within the constructs. Numerical estimates of the effectiveness of the interventions were also collected from participants to compare them with the published evidence.
  
  
  RESULTS
  Constructs clustered around three dimensions: "therapeutic impact," "behavior-dependent impact," and "impact facilitates general health." Smokers perceived impacts that are dependent on the individuals' behavior to offer small therapeutic impacts, while facilitating individuals' general health. These three characteristics were attributed to nonbiomedical interventions (e.g., talk-based interventions), while the opposite characteristics were attributed to biomedical interventions (i.e., medication and surgery). Numerical estimates showed that the effectiveness of stop-smoking interventions was underestimated relative to interventions to prevent heart disease.
  
  
  CONCLUSIONS
  The elicited dimensions provide a basis for communicating evidence concerning the effectiveness of medical interventions, with a view to increasing their use.
authors.affiliation: Department of Psychology, King's College London, London, UK. florian.vogt@kcl.ac.uk
authors.forename: Florian
authors.initials: F
authors.lastname: Vogt
authors.forename: Mark
authors.initials: M
authors.lastname: Ashworth
authors.forename: Sue
authors.initials: S
authors.lastname: Hall
authors.forename: Falko F
authors.initials: FF
authors.lastname: Sniehotta
authors.forename: Theresa M
authors.initials: TM
authors.lastname: Marteau
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D007407:Interviews as Topic; D008297:Male; D008875:Middle Aged; D025341:Principal Component Analysis; D012907:Smoking / Q000523:psychology*; D016540:Smoking Cessation / Q000523:psychology*; D011795:Surveys and Questionnaires; D055815:Young Adult