Complex Samples Ordinal Regression Odds Ratios
The Odds Ratios dialog box allows you to display the model-estimated cumulative odds ratios for specified factors and covariates. This feature is only available for models using the Logit link function. A single cumulative odds ratio is computed for all categories of the dependent variable except the last; the proportional odds model postulates that they are all equal.
Factors. For each selected factor, displays the ratio of the cumulative odds at each category of the factor to the odds at the specified reference category.
Covariates. For each selected covariate, displays the ratio of the cumulative odds at the covariate's mean value plus the specified units of change to the odds at the mean.
When computing odds ratios for a factor or covariate, the procedure fixes all other factors at their highest levels and all other covariates at their means. If a factor or covariate interacts with other predictors in the model, then the odds ratios depend not only on the change in the specified variable but also on the values of the variables with which it interacts. If a specified covariate interacts with itself in the model (for example, age*age), then the odds ratios depend on both the change in the covariate and the value of the covariate.
To Obtain Odds Ratios for Complex Samples Ordinal Regression
This feature requires SPSS® Statistics Premium Edition or the Complex Samples option.
- From the menus choose:
- Select a plan file. Optionally, select a custom joint probabilities file.
- Click Continue.
- In the Complex Samples Ordinal Regression dialog box, select at least one factor or covariate and click Odds Ratios.
- Choose the factors and covariates for which you want to produce odds ratios.
Optionally, you can set the reference category for factors and specify the units of change for covariates.