Page History

...

The uniqueness of values by observation or groups of observaobservations can be used to represent relationships efficiently. In cases where values are unque to observations

When possible the variable represented in IDVAR will have values from collected data (e.g., SPID, RECID), but variables with derived values may also be used (e.g., --SEQ).

1. When relationship datasets (e.g., SUPPxx, FAxx, CO, RELREC) relate back to split parent domains, the value of IDVAR will be from a variable with unique values for each observation. 

   1.