The ID statement specifies a variable in the DATA= data set that contains descriptive labels for the objects. The labels are used in the output and are copied to the OUT= data set. If there is more than one data matrix, only the ID values from the observations containing the first data matrix are used.
The ID variable is not used to establish any correspondence between observations and variables.
If the ID statement is omitted, the variable labels or names are used as object labels.