Value Labels or Formats (and Measurement Level)
This section blends two topics because in R they are inseparable. In both SAS and SPSS, assigning labels to values is independent of the variable's measurement level. In R, you can assign value labels only to variables whose measurement level is factor. To be more precise, only objects whose class is factor can have label attributes.
In SAS, a variable's measurement level of nominal, ordinal, or interval is not stored. Instead, you list the variable on a specific statement, such as CLASS or BY, to tell SAS that you wish to view it as categorical.
Example programs for value labels or formats (&measurement level)
SAS programming statements
* SAS Program to Assign Value Labels...