ROTATION Subcommand (CATPCA command)

The ROTATION subcommand specifies the method for rotation to a simple component structure.

  • When a rotation method is specified, both the unrotated loadings results and rotated loadings are displayed (if LOADING is specified on the PRINT or PLOT subcommand).
  • If VARIMAX, QUARTIMAX, or EQUAMAX is specified, the component transformation matrix is also displayed. If PROMAX or OBLIMIN is specified, the pattern and structure maxtrices are displayed, as well as the components correlation matrix.
  • Besides the loadings, rotation also affects component scores and category scores, for which only the rotated results are displayed.
  • The same command cannot contain both ROTATION and RESAMPLE subcommands.

The following alternatives are available:

NOROTATE. No rotation. This is the default setting.

VARIMAX. Varimax rotation. An orthogonal rotation method that minimizes the number of variables that have high loadings on each component. It simplifies the interpretation of the components.

QUARTIMAX. Quartimax rotation. A rotation method that minimizes the number of components needed to explain each variable. It simplifies the interpretation of the observed variables.

EQUAMAX. Equamax rotation. A rotation method that is a combination of the Varimax method, which simplifies the components, and the Quartimax method, which simplifies the variables. The number of variables that load highly on a component and the number of components needed to explain a variable are minimized .

PROMAX(kappa). Promax Rotation. An oblique (non-orthogonal) rotation, which allows components to be correlated. It can be calculated more quickly than a direct Oblimin rotation, so it is useful for large datasets. The amount of correlation (obliqueness) that is allowed is controlled by the kappa parameter. The value must be greater than or equal to 1 and less 10,000. The default value is 4.

OBLIMIN(delta). Direct Oblimin rotation. A method for oblique (non-orthogonal) rotation. When delta equals 0, components are most oblique. As delta becomes more negative, the components become less oblique. Positive values permit additional component correlation. The value must be less than or equal to 0.8. The default value is 0.

KAISER. Kaiser normalization. In the rotation process the loadings are divided by the square root of their communalities, to prevent relatively large loadings dominating the rotation. This is the default setting.

NOKAISER. Turn off Kaiser normalization.