User Guide

333
Crosstabs
Kappa. Cohen's kappa measures the agreement between the evaluations of two raters
when both are rating the same object. A value of 1 indicates perfect agreement. A
value of 0 in
dicates that agreement is no better than chance. Kappa is only available
for tables in which both variables use the same category values and both variables
havethesamenumberofcategories.
Risk. For 2 x
2 tables, a measure of the strength of the association between the
presence of a factor and the occurrence of an event. If the confidence interval for
the statistic includes a value of 1, you cannot assume that the factor is associated
with the ev
ent. The odds ratio can be used as an estimate or relative risk when the
occurrence of the factor is rare.
McNemar. A nonparametric test for two related dichotomous variables. Tests for
changes i
n responses using the chi-square distribution. Useful for detecting changes
in responses due to experimental intervention in "before-and-after" designs. For
larger square tables, the McNemar-Bowker test of symmetry is reported.
Cochran'
s and Mantel-Haenszel statistics.
Cochran's and Mantel-Haenszel statistics
can be used to test for independence between a dichotomous factor variable and a
dichotomous response variable, conditional upon covariate patterns defined by one or
more lay
er (control) variables. Note that while other statistics are computed layer by
layer, the Cochran's and Mantel-Haenszel statistics are computed once for all layers.