Please, please don't use the word 'trivial' lightly...ain't nothin' trivial around here! This is the insurance business, millions of records, and yes, families identified by one (the enrollee's) ssn.

This ssn/firstname/birthdate problem is common. We get data with lots of errors in it and must clean up messes not of our own creation.

At any rate, I've got to go thru each scanned subset of like ssn's, test for duplicate birthdates, and then test for duplicate, or almost duplicate, firstnames. So far, this has been an imperfect process for many reasons.