Workspace Node: Principal Components and Classification Analysis - Results - Variables Tab

In the Principal Components and Classification Analysis node dialog box, under the Results heading, select the Variables tab to access the following options.

Element Name Description
Factor coordinates of variables Select this check box to produce a spreadsheet with the factor coordinates of the active and supplementary variables (if selected via the Variables button of the Specifications - Quick tab). To distinguish between the two types of variables in the current analysis, the supplementary variables are marked with an asterisk (*). The factor coordinates are commonly referred to as factor loadings, and provide useful information for the interpretation of the factors. Refer to the Introductory Overview for additional details.
Plot var. factor coordinates, 2D Select this check box to produce a 2D scatterplot of the current set of factor coordinates for the selected pair of factors. Click the adjacent button to display the Select Two Factors for the Plot dialog box, where you can select factors for the factor axes.
Options for plot of factor coord The options in this group box can be used for including objects, such as the correlation (unit) circle, the vector lines, etc., in the Plot of factor coordinates (see above). Note that, by default, a plot with the unit circle and the vector lines will be produced, as will be the names (or numbers, if names are not available) of the variables.
Vectors (points to origin) Select this check box to plot the vector lines from the origin to the factor coordinates.
Unit circle Select this check box to plot the unit circle, encircling the factor coordinates. If the current analysis is based on the correlation matrix, then the area inside the unit circle represents the region of the valid (possible) factor coordinates (loadings). The closer a plotted variable is to the border of the circle, the better is its representation by the factors in the plot. The option of unit circle is not available if the current analysis is based on the covariance matrix rather than the correlation matrix (see the Analysis based on group box on the Specifications - Quick tab). However, the vector lines (see above) can still be produced, if desired.
Variable names Select this option button to display the names of the variables projected on the factor-plane.
Variable numbers Select this option button to display the numbers of the variables projected on the factor-plane.
No Names/Numbers Select this option button to plot the points for the factor coordinates without displaying the names or the numbers of the variables projected on the factor-plane.
Factor & variable correlations Select this check box to produce a spreadsheet that will display the correlations between the factors and the variables in the current analysis. These correlations are identical to the factor coordinates, if the current analysis is based on the correlation matrix. However, if the current analysis is based on the covariances, these values can be interpreted analogously to the factor loadings in a traditional factor analysis (see the Analysis based on group box on the Specifications - Quick tab). Refer to the Introductory Overview for additional details.
Communalities (Cosine2) Select this check box to produce a spreadsheet with the communalities. Communalities represent the proportion of variance accounted for in the respective variables by the given number of factors.
Contributions of variables Select this check box to produce a spreadsheet presenting the contributions of factors to the variance. These values are computed for the active cases only, and are helpful in interpreting the factor axes.
Eigenvalues Select this check box to produce a spreadsheet with the positive eigenvalues of the correlation or covariance matrix (depending on which was chosen for the analysis in the Analysis based on group box on the Specifications - Quick tab). Note that the displayed eigenvalues are computed from the correlations or covariances of the active variables only, even if supplementary variables were selected via the Variables button on the Specifications - Quick tab.
Eigenvectors Select this check box to produce a spreadsheet with the eigenvectors corresponding to each eigenvalue.
Scree plot Select this check box to produce a simple line plot of the eigenvalues, called a Scree plot (Cattell, 1966). The eigenvalues in this plot appear to level off at certain point. It is recommended that no more than the number of factors to the left of this point should be computed. Note that the scree plot will plot all the eigenvalues of the correlation or covariance matrix, irrespective of the Numbers of factors chosen for the current analysis.

Options / C. See Common Options.

OK Click the OK button to accept all the specifications made in the dialog box and to close it. The analysis results will be placed in the Reporting Documents node after running (updating) the project.