title: The influence of history on interobserver agreement for diagnosing actinic keratoses and malignant skin lesions.
abstract: BACKGROUND
  Quantifying interobserver diagnostic agreement is necessary to evaluate skin cancer screening programs, but estimates of variability are incomplete.
  
  
  OBJECTIVE
  We sought to measure agreement between dermatologists for diagnosing actinic keratoses (AKs) and malignant skin lesions and to determine the way in which blinding examiners to patient history affects agreement.
  
  
  METHODS
  We varied the amount of historical information available to examiners in two consecutive patient series (n = 50) presenting to a Veterans Affairs Medical Center dermatology clinic. Two dermatologists examined each patient independently.
  
  
  RESULTS
  Assessing historical features increased the kappa statistic for malignancy recognition from -0.04 to 0.76. kappa Statistics for diagnosing single AKs were 0.17 and 0.15, respectively, and 0.62 and 0.55 for multiple AKs.
  
  
  CONCLUSIONS
  Agreement was high for diagnosing malignant skin lesions when history was included in the evaluation. Agreement for multiple AKs was higher than for single AKs, although neither was influenced by inclusion of historical features.
authors.affiliation: Center for Health Services Research in Primary Care, Durham Veterans Affairs Medical Center, NC 27705, USA.
authors.forename: J D
authors.initials: JD
authors.lastname: Whited
authors.forename: R D
authors.initials: RD
authors.lastname: Horner
authors.forename: R P
authors.initials: RP
authors.lastname: Hall
authors.forename: D L
authors.initials: DL
authors.lastname: Simel
mesh_terms: D000368:Aged; D001706:Biopsy; D003880:Dermatology / Q000193:education; D006801:Humans; D007396:Internship and Residency; D007642:Keratosis / Q000175:diagnosis*; D008297:Male; D008487:Medical History Taking; D008875:Middle Aged; D015588:Observer Variation; D010808:Physical Examination; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D012878:Skin Neoplasms / Q000175:diagnosis*; D013223:Statistics as Topic