SPSS® 12.0 Command Syntax Reference

804 LOGISTIC REGRESSION
• The default output includes goodness-of-fit tests for the model (–2 log-likelihood, goodness-of-fit
statistic, Cox and Snell R 2 , and Nagelkerke R 2 ) and a classification table for
the predicted and observed group memberships. The regression coefficient, standard error
of the regression coefficient, Wald statistic and its significance level, and a multiple
correlation coefficient adjusted for the number of parameters (Atkinson, 1980) are
displayed for each variable in the equation.
Subcommand Order
• Subcommands can be named in any order. If the VARIABLES subcommand is not specified
first, a slash (/) must precede it.
• The ordering of METHOD subcommands determines the order in which models are estimated.
Different sequences may result in different models.
Syntax Rules
• Only one dependent variable can be specified for each LOGISTIC REGRESSION.
• Any number of independent variables may be listed. The dependent variable may not
appear on this list.
• The independent variable list is required if any of the METHOD subcommands are used
without a variable list or if the METHOD subcommand is not used. The keyword TO cannot
be used on any variable list.
• If you specify the keyword WITH on the VARIABLES subcommand, all independent variables
must be listed.
• If the keyword WITH is used on the VARIABLES subcommand, interaction terms do not
have to be specified on the variable list, but the individual variables that make up the
interactions must be listed.
• Multiple METHOD subcommands are allowed.
• The minimum truncation for this command is LOGI REG.
Operations
• Independent variables specified on the CATEGORICAL subcommand are replaced by sets
of contrast variables. In stepwise analyses, the set of contrast variables associated with a
categorical variable is entered or removed from the model as a single step.
• Independent variables are screened to detect and eliminate redundancies.
• If the linearly dependent variable is one of a set of contrast variables, the set will be
reduced by the redundant variable or variables. A warning will be issued, and the reduced
set will be used.
• For the forward stepwise method, redundancy checking is done when a variable is to be
entered into the model.
• When backward stepwise or direct-entry methods are requested, all variables for each
METHOD subcommand are checked for redundancy before that analysis begins.