Understanding Interobserver Agreement: The Kappa Statistic

360 May 2005 Family MedicineIn reading medical literature on diagnosis and inter-pretation of diagnostic tests, our attention is generallyfocused on items such as sensitivity, specificity, pre-dictive values, and likelihood ratios. These items ad-dress the validity of the test. But if the people who ac-tually interpret the test cannot agree on the interpreta-tion, the test results will be of little us suppose that you are preparing to give a lec-ture on community-acquired pneumonia. As you pre-pare for the lecture, you read an article titled, Diag-nosing Pneumonia by History and Physical Examina-tion, published in the Journal of the American Medi-cal Association in You come across a table inthe article that shows agreement on physical examina-tion findings of the chest. You see that there was 79% agreement on the presence of wheezing with a kappaof and 85% agreement on the presence of tactilefremitus with a Kappa of How do you interpretthese levels of agreement taking into account the kappastatistic?

agree or disagree simply by chance. The kappa statistic (or kappa coefficient) is the most commonly used statistic for this purpose. A kappa of 1 indicates perfect agreement, whereas a kappa of 0 indicates agree-ment equivalent to chance. A limitation of kappa is that it is affected by the prevalence of the finding under observation.

Loading..

Tags:

  Statistics, Agreement, Agree, Ment, Kappa, Agreem ent, The kappa statistic

Information

Related search queries