Categorical Regression Options
The Options dialog box allows you to select the initial configuration style, specify iteration and convergence criteria, select supplementary objects, and set the labeling of plots.
Supplementary Objects. This allows you to specify the objects that you want to treat as supplementary. Simply type the number of a supplementary object (or specify a range of cases) and click Add. You cannot weight supplementary objects (specified weights are ignored).
Initial Configuration. If no variables are treated as nominal, select the Numerical configuration. If at least one variable is treated as nominal, select the Random configuration.
Alternatively, if at least one variable has an ordinal or spline ordinal scaling level, the usual model-fitting algorithm can result in a suboptimal solution. Choosing Multiple systematic starts with all possible sign patterns to test will always find the optimal solution, but the necessary processing time rapidly increases as the number of ordinal and spline ordinal variables in the dataset increase. You can reduce the number of test patterns by specifying a percentage of loss of variance threshold, where the higher the threshold, the more sign patterns will be excluded. With this option, obtaining the optimal solution is not garantueed, but the chance of obtaining a suboptimal solution is diminished. Also, if the optimal solution is not found, the chance that the suboptimal solution is very different from the optimal solution is diminished. When multiple systematic starts are requested, the signs of the regression coefficients for each start are written to an external IBM® SPSS® Statistics data file or dataset in the current session. See the topic Categorical Regression Save for more information.
The results of a previous run with multiple systematic starts allows you to Use fixed signs for the regression coefficients. The signs (indicated by 1 and −1) need to be in a row of the specified dataset or file. The integer-valued starting number is the case number of the row in this file that contains the signs to be used.
Criteria. You can specify the maximum number of iterations that the regression may go through in its computations. You can also select a convergence criterion value. The regression stops iterating if the difference in total fit between the last two iterations is less than the convergence value or if the maximum number of iterations is reached.
Label Plots By. Allows you to specify whether variables and value labels or variable names and values will be used in the plots. You can also specify a maximum length for labels.
To Specify CATREG Options
This feature requires the Categories option.
- From the menus choose:
- In the Categorical Regression dialog box, click Options.