Standardization of interelement distances in repertory grid technique and its consequences for psychological interpretation of self-identity plots: An empirical study

Abstract

A. Hartmann (1992) questioned the methodico-statistical reliability of Euclidean distance values between grid elements developed by P. Slater (1977), which were subsequently used by many authors as “classic” parameters within the framework of Repertory Grid Technique (G. A. Kelly, 1955). Hartmann demonstrated that element distances from grids of different matrix sizes (i.e., the number of constructs) are not directly comparable even after standardization by means of the Unit of Expected Distance (Slater, 1977) and proposed an additional, double standardization to solve the problem. The clinical relevance of Hartmann's critique was studied using 233 empirical grids from psychological routine diagnostics–whose construct number could vary from 4 to 14–using the concept of self-identity plots (SIPs; H. Norn's & F. Makhlouf-Norris, 1976). A comparison of the results of both standardizations reveals that SIP findings, which are “inconspicuous” according to Slater, turn “conspicuous” significantly in double standardization. This is solely due to an increase in different forms of isolation (actual self isolation, ideal self isolation, double isolation). By contrast, the frequencies of self alienation and self convergence are even reduced. Furthermore, double standardization leads to remarkable modifications of SIP findings even when examining grids of equal matrix size.