PC program for comparing tracking indices in several independent groups.

A method for computing a measure of tracking based on Cohen's kappa statistic for one-sample longitudinal data sets was previously described and implemented. This paper shows how one may test the equality of several kappas, each computed from an independent longitudinal sample. Thus, it is possible to formally compare groups of individuals with regard to stability in growth (or adaptive) patterns.

Computation of Foulkes and Davis' nonparametric tracking index using GAUSS.

Foulkes and Davis (1981) define tracking as the maintenance of relative rank over a given time span. This paper outlines the development of their statistic, based on a set of individual growth profiles, which estimates the degree of tracking observed in a one-sample longitudinal data set and shows how confidence intervals for the corresponding population parameter may be constructed. An example using a measure of skeletal growth is given and a GAUSS program to do the computations is provided.