Statistical methods in epidemiology. v. Towards an understanding of the kappa coefficient.
OBJECTIVE
This paper introduces readers to the problem of measuring interrater agreement in observer variation studies. The most usual statistic to quote is the kappa coefficient which measures agreement having corrected for chance.


METHODS
The kappa coefficient for measuring agreement between two observers is introduced. Some pointers are given to determining sample size estimation.


RESULTS
Some properties of the kappa coefficient are illustrated by taking examples from the author's teaching experiences.


CONCLUSIONS
The kappa coefficient is recommended for measuring agreement in observer variation studies.
Rigby
A S
AS
Sheffield Children's Hospital, University of Sheffield, UK. a.s.rigby@sheffield.ac.uk
D004813:Epidemiology; D006801:Humans; D015588:Observer Variation; D011336:Probability; D012680:Sensitivity and Specificity; D013223:Statistics as Topic