Description: The administrators of Social Security offset-type defined benefit plans commonly encounter two difficulties when attempting to calculate the Primary Insurance Amount 'PIA' offset. The first difficulty is in obtaining the Social Security earnings history. The second difficulty is in performing the calculation itself. This paper explores the possibility of substituting a variant of the employee's final average salary for his or her Social Security Average Indexed Monthly Earnings 'AIME'. The acceptability of this substitution is then critiqued with illustrations. From Transactions of Society of Actuaries 1980, Vol. 32.