What can I elect if I was put in CSRS or CSRS Offset by mistake?

If you were placed in CSRS or CSRS Offset due to a qualifying retirement coverage error and you should have been in FERS, you may elect CSRS Offset or FERS. If you were placed in CSRS or CSRS Offset due to a qualifying retirement coverage error and you should have been in Social Security-Only, you may elect CSRS Offset or Social Security-Only. This is summarized in the following chart: You are in: And you belong in: You may elect: CSRS FERS CSRS Offset or FERS. CSRS Offset FERS CSRS Social Security-Only CSRS Offset or Social Security-Only. CSRS Offset Social Security-Only