psych (version 1.0-95)

fa.extension: Apply Dwyer's factor extension to find factor loadings for extended variables

Description

Dwyer (1937) introduced a method for finding factor loadings for variables not included in the original analysis. This is basically finding the unattenuated correlation of the extension variables with the factor scores. An alternative, which does not correct for factor reliability was proposed by Gorsuch (1997). This is an application of exploratory factor analysis with extensions to new variables.

Usage

fa.extension(Ro,Roe,fo,correct=TRUE)

Arguments

Ro

The correlation matrix that was factored

Roe

The correlations of the original variables with the extended variables

fo

The output from the fa function.

correct

correct=TRUE produces Dwyer's solution, correct=FALSE produces Gorsuch's solution

Value

• Factor Loadings of the exended variables on the original factors

Details

It is assumed that the original factor solution was found by the fa function.

References

Paul S. Dwyer (1937), The determination of the factor loadings of a given test from the known factor loadings of other tests. Psychometrika, 3, 173-178

Gorsuch, Richard L. (1997) New Procedure for Extension Analysis in Exploratory Factor Analysis Educational and Psychological Measurement, 57, 725-740

See Also

See Also as fa, principal, Dwyer

Examples

#The Dwyer Example
Ro <- Dwyer[1:7,1:7]
Roe <- Dwyer[1:7,8]
fo <- fa(Ro,2,rotate="none")
fa.extension(Ro,Roe,fo)

#an example from simulated data
 d <- sim.item(12)
 R <- cor(d)
 Ro <- R[c(1,2,4,5,7,8,10,11),c(1,2,4,5,7,8,10,11)]
 Roe <- R[c(1,2,4,5,7,8,10,11),c(3,6,9,12)]
 fo <- fa(Ro,2)
 fa.extension(Ro,Roe,fo)

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