MISSING Subcommand (CATREG command)
In CATREG, we consider a system missing value, user defined missing values,
and values less than 1 as missing values. However, in discretizing
a variable (see previous section), values less than 1 are considered
as valid values. The MISSING subcommand
allows you to indicate how to handle missing values for each variable.
LISTWISE. Exclude cases with missing values on the specified variables. The cases used
in the analysis are cases without missing values on the variables specified. This is the default
applied to all variables, when the MISSING subcommand is omitted or is specified
without variable names or keywords. Also, any variable that is not included in the subcommand gets
this specification.
MODEIMPU. Impute missing value with mode. All cases are included and the imputations are treated as valid observations for a given variable. When there are multiple modes, the smallest mode is used.
EXTRACAT. Impute missing values on a variable with an extra category indicator. This implies that objects with a missing value are considered to belong to the same (extra) category. This category is treated as nominal, regardless of the optimal scaling level of the variable.
- The
ALLkeyword may be used to indicate all variables. If it is used, it must be the only variable specification. - A mode or extra-category imputation is done before listwise deletion.