title: Interobserver and intraobserver variability in the clinical assessment of oral lichen planus.
abstract: BACKGROUND
  In 1978, a clinical definition of OLP was formulated by the WHO. To date, the validation results of this clinical definition have not been published. The aim of this study was to evaluate interobserver and intraobserver variability in the clinical assessment of oral lichen planus (OLP).
  
  
  METHODS
  Four clinicians examined a set of 159 clinical pictures of a white lesion in a group of 60 patients. Each reviewing examiner was asked to apply the WHO definition of OLP from 1978, and to categorise each case as either: (i) diagnostic of OLP, (ii) other definable lesion, or (iii) leukoplakia. After three months, each of the four reviewing clinicians was given the clinical pictures of 45 randomly retrieved cases from the original 60. Interobserver and intraobserver variability were assessed by calculation of unweighted kappa statistics.
  
  
  RESULTS
  Interobserver agreement varied from 0.43 (moderate) to 0.77 (substantial), while the intraobserver agreement varied from 0.62 (substantial) to 0.92 (good).
  
  
  CONCLUSIONS
  Although the clinical WHO definition of OLP seems to be more reproducible than the histopathological one, there is still a significant amount of subjectivity in using this definition. A set of clinical and histopathological diagnostic criteria with good interobserver and intraobserver agreements (kappa values > 0.8) is very important in enabling reproducible and reliable studies on OLP to be performed.
authors.affiliation: Department of Oral and Maxillofacial Surgery/Oral Pathology, Academic Centre for Dentistry Amsterdam (ACTA)/Academic Hospital Vrije Universiteit, Amsterdam, The Netherlands.
authors.forename: E H
authors.initials: EH
authors.lastname: van der Meij
authors.forename: K P
authors.initials: KP
authors.lastname: Schepman
authors.forename: D R
authors.initials: DR
authors.lastname: Plonait
authors.forename: T
authors.initials: T
authors.lastname: Axéll
authors.forename: I
authors.initials: I
authors.lastname: van der Waal
mesh_terms: D003937:Diagnosis, Differential; D006801:Humans; D007972:Leukoplakia, Oral / Q000175:diagnosis / Q000473:pathology; D017676:Lichen Planus, Oral / Q000175:diagnosis* / Q000473:pathology; D015588:Observer Variation; D015203:Reproducibility of Results; D009626:Terminology as Topic; D014944:World Health Organization