PLOT Subcommand (PREFSCAL command)

The PLOT subcommand controls the display of plots. By default, PREFSCAL displays the object points of the common space and, if applicable, the individual space weights.

  • Omitting the PLOT subcommand or specifying PLOT without keywords produces the default plots.
  • If a keyword(s) is specified, only the plot for that particular keyword(s) is displayed.
  • Inapplicable keywords (for example, STRESS with equal minimum and maximum number of dimensions on the CRITERIA subcommand) are silently ignored.
  • Multiple value lists are allowed for INDIVIDUAL, TRANSFORMATIONS, SHEPARD, FIT, and RESIDUALS. For each value list, a separate plot will be displayed.

NONE. No plots. PREFSCAL does not produce any plot.

MULTIPLE. Multiple random starts. Displays a stacked histogram of penalized Stress, displaying both Stress and penalty.

INITIAL. Initial common space. Displays a scatterplot matrix of the coordinates of the initial common space.

STRESS. Scree plot. Produces a lineplot of penalized Stress versus dimensions. This plot is only produced if the maximum number of dimensions is larger than the minimum number of dimensions.

COMMON. Common space. A scatterplot matrix of coordinates of the common space is displayed. This setting is the default.

WEIGHTS. Individual space weights. A scatterplot is produced for the individual space weights. This setting is only applicable if one of the individual differences models is specified on the MODEL subcommand. For the weighted Euclidean model, the weights for all sources are displayed in a plot, with one dimension on each axis. For the generalized Euclidean model, one plot is produced per dimension, indicating both rotation and weighting of that dimension for each source.

INDIVIDUAL(valuelist). Individual spaces. The coordinates of the individual spaces are displayed in scatterplot matrices. This setting is only applicable if one of the individual differences models is specified on the MODEL subcommand. For each source that is specified on the value list, a scatterplot matrix of coordinates of the individual space is displayed. The sources are specified by a number between 1 and the total number of sources or is specified by a value from the sourceid, which is specified on the INPUT subcommand.

TRANSFORMATIONS(valuelist). Transformation plots. A line plot is produced of the original proximities versus the transformed proximities. On the value list, the names (identifiers) for which the plot is to be produced must be specified. Because the CONDITION subcommand allows for the specification of multiple transformation lists, the value lists depend on the conditionality. In case of row-conditional transformations, the names are row identifiers (either a number between 1 and the total number of rows, or a value from the rowid, which is specified on the INPUT subcommand). In the case of matrix-conditional transformations, the values indicate sources identifiers (either a number between 1 and the total number of sources, or a value from the sourceid, which is specified on the INPUT subcommand). An unconditional transformation only consists of one list and does not allow further specification.

SHEPARD(valuelist). Shepard plots. The original proximities versus both transformed proximities and distances. The distances are indicated by points, and the transformed proximities are indicated by a line. On the value list, the names (identifiers) for which the plot is to be produced must be specified. Because the CONDITION subcommand allows for the specification of multiple transformation lists, the value lists depend on the conditionality. In case of row-conditional transformations, the names are row identifiers (either a number between 1 and the total number of rows, or a value from the rowid, which is specified on the INPUT subcommand). In the case of matrix-conditional transformations, the values indicate sources identifiers (either a number between 1 and the total number of sources, or a value from the sourceid, which is specified on the INPUT subcommand). An unconditional transformation only consists of one list and does not allow further specification.

FIT(valuelist). Scatterplots of Fit. The transformed proximities versus the distances are plotted in a scatterplot. On the value list, the names (identifiers) of the sources for which the plot is to be produced must be specified. The sources are specified by a number between 1 and the total number of sources or are specified by a value from the sourceid, which is specified on the INPUT subcommand.

RESIDUALS(valuelist). Residuals plots. The transformed proximities versus the residuals (transformed proximities minus distances) are plotted in a scatterplot. On the value list, the names (identifiers) of the sources for which the plot is to be produced must be specified. The sources are specified by a number between 1 and the total number of sources or are specified by a value from the sourceid, which is specified on the INPUT subcommand.

Example

PREFSCAL var01 TO var15
  /INPUT = SOURCE(6)
  /MODEL = WEIGHTED
  /CRITERIA = DIMENSIONS(3)
  /PLOT = COMMON 
          INDIVIDUAL(2) 
          TRANSFORMATIONS(1 TO 42)(1 2)
          FIT(2).
  • Here, the syntax specifies a weighted Euclidean model with six sources in three dimensions.
  • COMMON produces a scatterplot matrix defined by dimensions 1, 2, and 3.
  • A scatterplot matrix with threedimensions is produced only for the source 2.
  • Two transformation plots are produced, one plot with all 42 rows and one plot with only row 1 and 2. Rows are specified with the TRANSFORMATIONS keyword because the default value on CONDITION is ROW.
  • A scatterplot of fit is produced for the source 2.