Complex Samples Logistic Regression Odds Ratios

The Odds Ratios dialog box allows you to display the model-estimated odds ratios for specified factors and covariates. A separate set of odds ratios is computed for each category of the dependent variable except the reference category.

Factors. For each selected factor, displays the ratio of the 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 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 Logistic Regression

This feature requires the Complex Samples option.

  1. From the menus choose:

    Analyze > Complex Samples > Logistic Regression...

  2. Select a plan file. Optionally, select a custom joint probabilities file.
  3. Click Continue.
  4. In the Complex Samples Logistic Regression dialog box, select at least one factor or covariate and click Odds Ratios.
  5. 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.