Grouping (or Coding) Variable

A grouping (or coding) variable is used to identify group membership for individual cases in the data file. Typically, the grouping variable is categorical (i.e., contains either discrete values, e.g., 1, 2, 3, ...,

or a few text values, e.g., MALE, FEMALE)

and the values are referred to as codes (they can be integer values or integer values with text value equivalents).