ANALYSIS Subcommand (PRINCALS command)

ANALYSIS specifies the variables to be used in the computations and the optimal scaling level used by PRINCALS to quantify each variable or variable list.

  • If ANALYSIS is not specified, an ordinal level of optimal scaling is assumed for all variables.
  • The specification on ANALYSIS is a variable list and an optional keyword in parentheses to indicate the optimal scaling level.
  • The variables on the variable list must also be specified on the VARIABLES subcommand.
  • Variables listed on the VARIABLES subcommand but not on the ANALYSIS subcommand can still be used to label object scores on the PLOT subcommand.

The following keywords can be specified to indicate the optimal scaling level:

MNOM. Multiple nominal. The quantifications can be different for each dimension. When all variables are multiple nominal, PRINCALS gives the same results as HOMALS.

SNOM. Single nominal. PRINCALS gives only one quantification for each category. Objects in the same category (cases with the same value on a variable) obtain the same quantification. When DIMENSION=1 and all variables are SNOM, this solution is the same as that of the first HOMALS dimension.

ORDI. Ordinal. This is the default for variables listed without optimal scaling levels and for all variables if the ANALYSIS subcommand is not used. The order of the categories of the observed variable is preserved in the quantified variable.

NUME. Numerical. This is the interval or ratio level of optimal scaling. PRINCALS assumes that the observed variable already has numerical values for its categories. When all variables are at the numerical level, the PRINCALS analysis is analogous to classical principal components analysis.

These keywords can apply to a variable list as well as to a single variable. Thus, the default ORDI is not applied to a variable without a keyword if a subsequent variable on the list has a keyword.