RESTRICTIONS Subcommand (PROXSCAL command)

PROXSCAL provides two types of restrictions for the user to choose from. The first type fixes (some) coordinates in the configuration. The second type specifies that the common space is a weighted sum of independent variables.

COORDINATES. Fixed coordinates. A parenthesized IBM® SPSS® Statistics data filename must be specified containing the fixed coordinates for the common space. A variable list may be given, if some specific variables need to be selected from the external file. If the variable list is omitted, the procedure automatically selects the first MAXDIM variables in the external file, where MAXDIM is the maximum number of dimensions requested for the analysis on the CRITERIA subcommand. A missing value indicates that a coordinate on a dimension is free. The coordinates of objects with nonmissing values are kept fixed during the analysis. The number of cases for each variable must be equal to the number of objects.

VARIABLES. Independent variables. The common space is restricted to be a linear combination of the independent variables in the variable list. A parenthesized IBM SPSS Statistics data file must be specified containing the independent variables. If the variable list is omitted, the procedure automatically selects all variables in the external file. Instead of the variable list, the user may specify the keyword FIRST(n), where n is a positive integer, to select the first n variables in the external file. The number of cases for each variable must be equal to the number of objects. After the variable selection specification, we may provide a list of keywords (in number equal to the number of the independent variables) indicating the transformations for the independent variables.