The application range of Cohen's Kappa is extended to the field of sequential observation data, where omission mistakes of an observer may often occur. It is shown how the omission mistakes can be incorporated into the calculation of the Kappa coefficient without violating the statistic it is based on. The enhanced coefficient is termed Kappa…

Existing item response data on three achievement tests were used to compare the use of two sequential testing procedures with conventional testing for purposes of dichotomous decisions on each of the three dimensions. (Author/AG)