G. R. Ducharme and Y. Lepage (1986, J. Roy. Statist. Soc. Ser. B48, 197-205) presented the strong collapsibility of odds ratio in 22K tables. However, the concept is not suitable for an ordinal background variable since it is meaningless to pool nonadjacent levels in this case. In this paper, we...

We find two fundamental statistics in discriminant analysis on which many influence measures depend. A few other measures are also proposed and discussed. Approximate contours of the measure can be plotted to reveal influence information.