• ARTICLES

When is my grid cognitively complex and when is it simple? Some approaches to deciding

Bell, R. C.

Keywords:
cognitive complexity, intensity, PVAFF, random grids, number of factors

Abstract:
Indices which purport to measure cognitive complexity-simplicity in repertory grid data have proliferated since Bieri introduced the concept in 1955, and a number of studies have shown how two correlation based measures, Bannister’s intensity index (the average correlation) and the amount of variance accounted for by the first principal component of these correlations [PVAFF], are related. The usefulness of these indices in decision making contexts is limited by the fact that users, unless they have employed a standard grid on many occasions, have no idea what constitutes a normal index value and what is abnormal. Here we use comparisons with indices derived from random data to identify abnormal indices and in doing so show limitations with both intensity and PVAFF, and show how an elaboration of the latter, determination of the number of components, provides a more informative basis for classifying construct systems as fragmented, monolithic, or complex.