ABSTRACT
Coefficient ................................................................................................................. 414 20.4.3 Kappa ............................................................................................................................ 415 20.4.4 Directional Problems of an “Omnibus” Index............................................................. 418
20.5 Agreement in Ordinal Data ....................................................................................................... 419 20.5.1 Individual Discrepancies .............................................................................................. 419 20.5.2 Weighting of Disagreements ........................................................................................ 420 20.5.3 Proportion of Weighted Agreement.............................................................................. 421 20.5.4 Demarcation of Ordinal Categories ............................................................................. 423 20.5.5 Artifactual Arrangements ............................................................................................. 423 20.5.6 Weighted Kappa............................................................................................................ 424 20.5.7 Correlation Indexes....................................................................................................... 425
20.6 Agreement in Nominal Data ..................................................................................................... 425 20.6.1 Substantively Weighted Disagreements ....................................................................... 425 20.6.2 Choice of Categories .................................................................................................... 426 20.6.3 Conversion to Other Indexes ........................................................................................ 426 20.6.4 Biased Agreement in Polytomous Data ....................................................................... 427
20.7 Agreement in Dimensional Data ............................................................................................... 427 20.7.1 Analysis of Increments................................................................................................. 427 20.7.2 Analysis of Correlation ................................................................................................ 429 20.7.3 Analysis of Intraclass Correlation................................................................................ 430
20.8 Stochastic Procedures ................................................................................................................ 431 20.9 Multiple Observers .................................................................................................................... 432
20.9.1 Categorical Data ........................................................................................................... 432 20.9.2 Dimensional Data ......................................................................................................... 432
References .............................................................................................................................................. 432 Exercises ............................................................................................................................. 432
A striking feature of modern medical statistics has been the relative absence of attention to the scientific quality of raw data. Despite the many methods developed for sampling, receiving, and analyzing data, and for drawing conclusions about importance or “significance,” the scientific suitability, accuracy, and reproducibility of the basic information has not been a major focus of concern.
