OpenRepGrid (version 0.1.9)

indexPvaff: Percentage of Variance Accounted for by the First Factor (PVAFF)

Description

The PVAFF is used as a measure of cognitive complexity. It was introduced in an unpublished PhD thesis by Jones (1954, cit. Bonarius, 1965). To calculate it, the 'first factor' is extracted from the construct correlation matrix by principal component analysis. The PVAFF reflects the amount of variation that is accounted for by a single linear component. If a single latent component is able to explain the variation in the grid, the cognitive complexity is said to be low. In this case the construct system is regarded as 'simple' (Bell, 2003).

Usage

indexPvaff(x)

Arguments

x

repgrid object.

Development

TODO: Results have not yet been checked against other grid programs.

Details

The percentage of variance is calculated using the corelation matrix of te constructs submitted to svd.

References

Bell, R. C. (2003). An evaluation of indices used to represent construct structure. In G. Chiari & M. L. Nuzzo (Eds.), Psychological Constructivism and the Social World (pp. 297-305). Milan: FrancoAngeli.

Bonarius, J. C. J. (1965). Research in the personal construct theory of George A. Kelly: role construct repertory test and basic theory. In B. A. Maher (Ed.), Progress in experimental personality research (Vol. 2). New York: Academic Press.

James, R. E. (1954). Identification in terms of personal constructs (Unpublished doctoral thesis). Ohio State University, Columbus, OH.

Examples

indexPvaff(bell2010)
   indexPvaff(feixas2004)

   # save results to object
   p <- indexPvaff(bell2010)
   p