title: Diagnostic test evaluation by patient-outcome study in homeopathy: balancing of feasibility and validity.
abstract: BACKGROUND
  Signs and symptoms can be considered as diagnostic tests, updating prior odds by applying Bayes' theorem. In homeopathy, signs and symptoms guide the doctor when prescribing appropriate medicines but the powers of these indicators are largely based on common experience.
  
  
  OBJECTIVE
  We want to know whether it is possible to calculate the power of arguments of signs and symptoms indicating homeopathic medicines, expressed in likelihood ratios.
  
  
  METHODS
  An observational patient-outcome study as advocated for diagnostic test evaluation. There was no independent observation of symptoms and results. Instead, observers were extensively trained in assessing each other's cases and the process was regularly monitored.
  
  
  RESULTS
  A total of 4072 prescriptions for 4094 patients were recorded. The relation between six clinical symptoms and outcome was calculated. Variance between observers in assessing symptoms and results were considerable. Some indications of confirmation bias were detected by follow-up, and 48 statistically significant likelihood ratios regarding six symptoms were calculated.
  
  
  CONCLUSIONS
  A diagnostic patient-outcome study within homeopathy collecting a large amount of data is demonstrated. Results partly confirm clinical practice at a 95% confidence level. This kind of research could validate knowledge from practical experience.
authors.affiliation: homeopathic physician, Committee for Methods and Validation of the Dutch association for homeopathic doctors (VHAN), Wageningen, the Netherlands. lexrtn@concepts.nl
authors.forename: A L B
authors.initials: AL
authors.lastname: Rutten
authors.forename: C F
authors.initials: CF
authors.lastname: Stolper
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001499:Bayes Theorem; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D016001:Confidence Intervals; D003955:Diagnostic Tests, Routine / Q000379:methods*; D005260:Female; D006705:Homeopathy / Q000379:methods*; D006801:Humans; D016013:Likelihood Functions; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D017063:Outcome Assessment, Health Care; D010818:Practice Patterns, Physicians' / Q000706:statistics & numerical data; D018709:Statistics, Nonparametric