Multiple Correspondence Analysis Missing Values

The Missing Values dialog box allows you to choose the strategy for handling missing values in analysis variables and supplementary variables.

Missing Value Strategy. Choose to exclude missing values (passive treatment), impute missing values (active treatment), or exclude objects with missing values (listwise deletion).

• Exclude missing values; for correlations impute after quantification. Objects with missing values on the selected variable do not contribute to the analysis for this variable. If all variables are given passive treatment, then objects with missing values on all variables are treated as supplementary. If correlations are specified in the Output dialog box, then (after analysis) missing values are imputed with the most frequent category, or mode, of the variable for the correlations of the original variables. For the correlations of the optimally scaled variables, you can choose the method of imputation. Select Mode to replace missing values with the mode of the optimally scaled variable. Select Extra category to replace missing values with the quantification of an extra category. This implies that objects with a missing value on this variable are considered to belong to the same (extra) category.
• Impute missing values. Objects with missing values on the selected variable have those values imputed. You can choose the method of imputation. Select Mode to replace missing values with the most frequent category. When there are multiple modes, the one with the smallest category indicator is used. Select Extra category to replace missing values with the same quantification of an extra category. This implies that objects with a missing value on this variable are considered to belong to the same (extra) category.
• Exclude objects with missing values on this variable. Objects with missing values on the selected variable are excluded from the analysis. This strategy is not available for supplementary variables.

To Specify Multiple Correspondence Analysis Missing Values

This feature requires the Categories option.

1. From the menus choose:

   Analyze > Dimension Reduction > Optimal Scaling...

2. In the Multiple Correspondence Analysis dialog box, click Missing.