EFA.dimensions (version 0.1.7.2)

IMAGE_FA: Image factor analysis

Description

Image factor analysis

Usage

IMAGE_FA(data, corkind, Nfactors=NULL, Ncases=NULL, rotate, ppower, verbose)

Arguments

data

An all-numeric dataframe where the rows are cases & the columns are the variables, or a correlation matrix with ones on the diagonal.The function internally determines whether the data are a correlation matrix.

corkind

The kind of correlation matrix to be used if data is not a correlation matrix. The options are 'pearson', 'kendall', 'spearman', 'gamma', and 'polychoric'. Required only if the entered data is not a correlation matrix.

Nfactors

The number of factors to extract.

Ncases

The number of cases. Required only if data is a correlation matrix.

rotate

The factor rotation method. The options are: 'PROMAX', , and 'none'.

ppower

The power value to be used in a promax rotation (required only if rotate = 'PROMAX'). Suggested value: 3

verbose

Should detailed results be displayed in console? TRUE (default) or FALSE

Value

A list with the following elements:

eigenvalues

The eigenvalues

loadingsNOROT

The unrotated factor loadings

loadingsROT

The rotated factor loadings (for varimax rotation)

structure

The structure matrix (for promax rotation)

pattern

The pattern matrix (for promax rotation)

correls

The correlations between the factors (for promax rotation)

cormat_reproduced

The reproduced correlation matrix, based on the rotated loadings

Details

"Image analysis is a principal factor variant in its usual application. As in the case of the principal axes with estimated communalities procedure, it is a principal factor variant in the sense that, after appropriate alterations are made to the correlation matrix, that matrix can be submitted to a principal factor program to find the desired factors. The program will then minimize the residuals of the particular matrix submitted. The differences in image analysis and other principal factor variants lie primarily in the alterations of the correlation matrix before the factors are extracted. Image factors can also be extracted by maximum likelihood procedures (Joreskog, 1969b)." (Gorsuch, 1974, p. 103)

Image analysis is a common factor analysis of the predictable variance of a set of variables. Each variable, Xi, is regressed on all other variables to obtain the predicted Xi values. The covariance matrix of the predicted Xis is then factored to produce an image analysis. The image of a variable is the portion of a variable which is predicted from other variables.

The present function is an implementation of the Harris (1962) variant of this procedure (see also Velicer, 1974), which is a noniterative approximation to canonical component analysis. The results are identical to the image factor analysis results that are produced by SAS and SPSS.

References

Gorsuch, R. L. (1983). Factor analysis ( 2nd ed. ). Hillsdale, N.J.: Erlbaum, 1983. Guttman, L. (1953). Image theory for the structure of quantitative variates. Psychometrika 18, 277-296. Harris, C. W. (1962). Some Rao-Guttman relationships. Psychometrika, 27, 247-63. Velicer, W. F. (1974). A comparison of the stability of factor analysis, principal component analysis, and rescaled image analysis. Educational and Psychological Measurement, 34(3), 563-572.

Examples

# NOT RUN {
# the Harman (1967) correlation matrix
IMAGE_FA(data_Harman, Nfactors=2, Ncases=305, rotate='PROMAX', ppower = 4, verbose=TRUE)

# Rosenberg Self-Esteem scale items
IMAGE_FA(data_RSE, corkind='gamma', Nfactors=2, rotate='PROMAX', ppower = 4, verbose=TRUE)

# NEO-PI-R scales
IMAGE_FA(data_NEOPIR, corkind='pearson', Nfactors=5, rotate='PROMAX', ppower = 4, verbose=TRUE)
# }