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Modeling and Multivariate Methods - SAS

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Chapter 19 Analyzing Principal Components <strong>and</strong> Reducing Dimensionality 489<br />

Platform Options<br />

than do orthogonal rotations. However, a consequence of correlated factors is that there is no single<br />

unambiguous measure of the importance of a factor in explaining a variable.<br />

Available orthogonal rotation methods are:<br />

Varimax specifies the orthogonal varimax rotation. The corresponding <strong>SAS</strong> Proc Factor option<br />

specification is ROTATE=ORTHOMAX with GAMMA=1.<br />

Biquartimax specifies the orthogonal biquartimax rotation. The corresponding <strong>SAS</strong> Proc Factor option<br />

specification is ROTATE=ORTHOMAX with GAMMA=0.5.<br />

Equamax specifies the orthogonal equamax rotation. The corresponding <strong>SAS</strong> Proc Factor option<br />

specification is ROTATE=ORTHOMAX with GAMMA=number of factors/2.<br />

Factorparsimax specifies the orthogonal factor parsimax rotation. The corresponding <strong>SAS</strong> Proc Factor<br />

option specification is ROTATE=ORTHOMAX with GAMMA=number of variables.<br />

Orthomax specifies the orthogonal orthomax rotation with orthomax weight p. The corresponding <strong>SAS</strong><br />

Proc Factor option specification is either ROTATE=ORTHOMAX or ROTATE=ORTHOMAX(p),<br />

which specifies p as the orthomax weight or the GAMMA=value. The default p value is 1 unless<br />

specified otherwise in the GAMMA= option. For additional information on orthomax weight, see the<br />

<strong>SAS</strong> documentation, “Simplicity Functions for Rotations.”<br />

Parsimax specifies the orthogonal parsimax rotation. The corresponding <strong>SAS</strong> Proc Factor option<br />

specification is ROTATE=ORTHOMAX with GAMMA=[(nvar(nfact - 1))/(nvar + nfact - 2)] where<br />

nvar is the number of variables, <strong>and</strong> nfact is the number of factors.<br />

Quartimax specifies the orthogonal quartimax rotation. The corresponding <strong>SAS</strong> Proc Factor option<br />

specification is ROTATE=ORTHOMAX with GAMMA=0.<br />

Available oblique rotation methods are:<br />

Biquartimin specifies the oblique biquartimin rotation. The corresponding <strong>SAS</strong> Proc Factor option<br />

specification is ROTATE=OBLIMIN(.5) or ROTATE=OBLIMIN with TAU=.5.<br />

Covarimin specifies the oblique covarimin rotation. The corresponding <strong>SAS</strong> Proc Factor option<br />

specification is ROTATE=OBLIMIN(1) or ROTATE=OBLIMIN with TAU=1.<br />

Obbiquartimax specifies the oblique biquartimax rotation. The corresponding <strong>SAS</strong> Proc Factor option<br />

specification is ROTATE=OBBIQUARTIMAX.<br />

Obequamax specifies the oblique equamax rotation. The corresponding <strong>SAS</strong> Proc Factor option<br />

specification is ROTATE=OBEQUAMAX.<br />

Obfactorparsimax specifies the oblique factor parsimax rotation. The corresponding <strong>SAS</strong> Proc Factor<br />

option specification is ROTATE=OBFACTORPARSIMAX.<br />

Oblimin specifies the oblique oblimin rotation with oblimin weight p. The corresponding <strong>SAS</strong> Proc<br />

Factor option specification is ROTATE=OBLIMIN, where the default p value is zero, unless specified<br />

otherwise in the TAU= option. ROTATE=OBLIMIN(p) specifies p as the oblimin weight or the TAU=<br />

value. For additional information on oblimin weight, see the <strong>SAS</strong> documentation, “Simplicity<br />

Functions for Rotations.”

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