title: Method for appraising model validity of randomised controlled trials of homeopathic treatment: multi-rater concordance study.
abstract: BACKGROUND
  A method for assessing the model validity of randomised controlled trials of homeopathy is needed. To date, only conventional standards for assessing intrinsic bias (internal validity) of trials have been invoked, with little recognition of the special characteristics of homeopathy. We aimed to identify relevant judgmental domains to use in assessing the model validity of homeopathic treatment (MVHT). We define MVHT as the extent to which a homeopathic intervention and the main measure of its outcome, as implemented in a randomised controlled trial (RCT), reflect 'state-of-the-art' homeopathic practice.
  
  
  METHODS
  Using an iterative process, an international group of experts developed a set of six judgmental domains, with associated descriptive criteria. The domains address: (I) the rationale for the choice of the particular homeopathic intervention; (II) the homeopathic principles reflected in the intervention; (III) the extent of homeopathic practitioner input; (IV) the nature of the main outcome measure; (V) the capability of the main outcome measure to detect change; (VI) the length of follow-up to the endpoint of the study. Six papers reporting RCTs of homeopathy of varying design were randomly selected from the literature. A standard form was used to record each assessor's independent response per domain, using the optional verdicts 'Yes', 'Unclear', 'No'. Concordance among the eight verdicts per domain, across all six papers, was evaluated using the kappa (κ) statistic.
  
  
  RESULTS
  The six judgmental domains enabled MVHT to be assessed with 'fair' to 'almost perfect' concordance in each case. For the six RCTs examined, the method allowed MVHT to be classified overall as 'acceptable' in three, 'unclear' in two, and 'inadequate' in one.
  
  
  CONCLUSIONS
  Future systematic reviews of RCTs in homeopathy should adopt the MVHT method as part of a complete appraisal of trial validity.
authors.affiliation: British Homeopathic Association, Luton, UK. rmathie@britishhomeopathic.org
authors.forename: Robert T
authors.initials: RT
authors.lastname: Mathie
authors.forename: Helmut
authors.initials: H
authors.lastname: Roniger
authors.forename: Michel
authors.initials: M
authors.lastname: Van Wassenhoven
authors.forename: Joyce
authors.initials: J
authors.lastname: Frye
authors.forename: Jennifer
authors.initials: J
authors.lastname: Jacobs
authors.forename: Menachem
authors.initials: M
authors.lastname: Oberbaum
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Bordet
authors.forename: Chaturbhuja
authors.initials: C
authors.lastname: Nayak
authors.forename: Gilles
authors.initials: G
authors.lastname: Chaufferin
authors.forename: John A
authors.initials: JA
authors.lastname: Ives
authors.forename: Flávio
authors.initials: F
authors.lastname: Dantas
authors.forename: Peter
authors.initials: P
authors.lastname: Fisher
mesh_terms: D006705:Homeopathy / Q000379:methods*; D006801:Humans; D017063:Outcome Assessment, Health Care; D016032:Randomized Controlled Trials as Topic / Q000592:standards*; D015203:Reproducibility of Results