RESTRICTIONS Subcommand (PREFSCAL command)

PREFSCAL allows (some) coordinates to be fixed in the common space configuration. Fixing an entire set (all row objects or all column objects) corresponds to performing external unfolding.

ROW. Row restriction. PREFSCAL allows one row object, multiple row objects, or all row objects to be free (NONE) or fixed to given coordinates (COORDINATES).

COLUMN. Column restriction. PREFSCAL allows one column object, multiple column objects, or all column objects to be free (NONE) or fixed to given coordinates (COORDINATES).

ROW or COLUMN Keywords

NONE. No restriction. The specified set of objects (ROW or COLUMN) has no restriction.

COORDINATES. Coordinates must be followed by a filespec in parentheses to specify the external IBM® SPSS® Statistics data file that contains the fixed coordinates for the specified set of objects. Following the parenthesized filespec, a variable list can be given. If the variable list is omitted, the procedure automatically selects the first MAXDIM variables in the external IBM SPSS Statistics data file, where MAXDIM is the maximum number of dimensions that are requested for the analysis on /CRITERIA = DIMENSIONS(min, max).

  • The number of cases for each variable in the external IBM SPSS Statistics data file must be equal to the number of objects of the specified set (ROW or COLUMN).
  • A missing value can be used to indicate that the coordinate on that dimension is free. The coordinates of objects with nonmissing values are kept fixed during the analysis.

Example

PREFSCAL var01 TO var15
  /RESTRICTIONS = ROW(NONE)
  /RESTRICTIONS = COLUMN(COORDINATES ("indcol.sav")).
  • In this example, there are 15 column objects.
  • The coordinates of the row objects are not restricted. Although this specification is the default, it is explicitly stated here in the syntax.
  • The column objects have restrictions on the coordinates. The fixed coordinates are specified in the IBM SPSS Statistics data file indcol.sav. If indcol.sav contains more than two variables, only the first two variables are taken as fixed coordinates, because the maximum dimensionality is 2, and specific variables on the RESTRICTIONS subcommand are not given.