MEASURES OF INDIVIDUAL AND GROUP CHANGES IN ORDERED CATEGORICAL-DATA - APPLICATION TO THE ADL STAIRCASE

The aim was to describe the application of a non-parametric method to a study of changes in activities of daily living (ADL) measured by a 1 0-level ordinal scale, the Staircase of ADL, in a population of 70-yea r-old persons followed to the age of 76 (n=371), The statistical metho d takes account of the fact that change cannot be defined by differenc es and can separately measure the level of change for the group and fo r the individuals, This is demonstrated step by step, Measures of chan ge for the subgroups, men and women, are also given. As a group, there was a systematic increase in ADL dependence between the ages of 70 an d 76 years, The individual pattern of change was more dispersed betwee n 73 and 76 years of age. Individual variations in ADL changes with in creasing age were small compared to the systematic change for ADL for the subgroups of men and women, The systematic change in ADL follows a pattern with ''one step at a time'' for women and ''many steps at a t ime'' for men. In conclusion, this new statistical method provides a v aluable tool for detailed information of individual as well as group c hanges in longitudinal studies.