In Reply

Our plain-English summary of In Reply, by L. Brcic, G. Vlacic, F. Quehenberger, et al (Archives of Pathology & Laboratory Medicine, 2018).

The study

• Authors: L. Brcic, G. Vlacic, F. Quehenberger, I. Kern
• Journal: Archives of Pathology & Laboratory Medicine
• Published: 2018;142(11):1311-1312
• Type of article: Letter, Comment
• Cited by: 1 article, as counted by NIH iCite
• Read it: PubMed · Publisher

In plain English

This is a reply letter, not a new study. The authors answered a letter questioning the statistics in their earlier article on how consistently pathologists classify malignant pleural mesothelioma subtypes. That article measured agreement with kappa, a statistic for agreement beyond chance. The authors corrected an error: the article said they used Cohen's kappa, but they had actually used Fleiss' kappa. They said the error arose during their own editing and was overlooked. They explained that kappa depends on how common each category is because of its correction for chance. They added that for symmetrical tables Fleiss' kappa equals Cohen's kappa, so it shares the weakness the letter writers raised. In the letter writers' example table, if all 10 disagreements went one way, Cohen's kappa would rise while Fleiss' kappa would stay unchanged. Fleiss' kappa, they said, is not necessarily zero when raters judge independently. In their example it was 0.111. The authors concluded that kappa-type measures depend on prevalence by their very nature. An editor's note said a correction appeared in the August 2018 issue.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Letter to the editor (authors' reply to a methodological critique of their earlier article); no new data
• Who was studied: No patients were studied in this letter. It concerns the authors' earlier article on interobserver and intraobserver reproducibility of histologic subtyping of malignant pleural mesothelioma.
• Main results:
  • The authors corrected their earlier article: they had used Fleiss' kappa, not Cohen's kappa as stated, to measure agreement.
  • The authors said the error occurred during their own editing and was overlooked.
  • The authors stated that kappa's dependence on prevalence arises from its correction for chance.
  • For symmetrical tables, Fleiss' kappa is the same as Cohen's kappa and so is affected by the same weakness the letter writers raised.
  • In the letter writers' combined example table, if all 10 disagreements were of the type where pathologist 1 rates positive and pathologist 2 rates negative, with agreeing ratings unchanged, Cohen's kappa would increase while Fleiss' kappa would stay unchanged.
  • A shortcoming of Fleiss' kappa is that it is not necessarily zero when raters are independent. In the authors' example, Cohen's kappa was zero and Fleiss' kappa was 0.111.
• The authors' conclusion: The authors concluded that kappa-type measures of agreement depend on prevalence by their very nature, and that Fleiss' kappa is unaffected by an asymmetric distribution of disagreements.

Topics

The National Library of Medicine indexes this study under subjects our site covers: Lung cancer, Mesothelioma.

Related studies

• Reproducibility of Malignant Pleural Mesothelioma Histopathologic Subtyping — L. Brcic, G. Vlacic, et al. (2018)
• In reply: asbestos, carcinogenicity, and public policy — W.J. Nicholson, E.M. Johnson, et al. (1990)
• Reply to Dr. Dunnigan. Chrysotile as a mesothelial carcinogen in man — A. Churg (1988)
• In Reply to "Malignant Mesothelioma and Its Nonasbestos Causes" — R.L. Attanoos, A. Churg, et al. (2019)
• Reply to Mirabelli et al. Is Mesothelioma Unrelated to the Lung Asbestos Burden? Comment on "Visonà et al. Inorganic Fiber Lung Burden in Subjects with Occupational and/or Anthropogenic Environmental Asbestos Exposure in Broni (Pavia, Northern Italy): An SEM-EDS Study on Autoptic Samples. Int. J. Environ. Res. Public Health 2021, 18, 2053" — S.D. Visonà, S. Capella, et al. (2021)
• A critique of a review on the relationship between asbestos exposure and the risk of mesothelioma: reply — C. La Vecchia, P. Boffetta (2014)

Browse more research in Archives of Pathology & Laboratory Medicine, or return to medical research.