the current number of employees and the actuarial cost method being used. As noted earlier, the actuarial cost method must take into consideration such factors as employee turnover, mortality, and the treatment of actuarial gains and losses. However, the APB did not specify which actuarial cost method to use.
Past Service Cost
When a pension plan is adopted, the employees are usually given credit for previous years of service. These benefits were referred to as past service cost and were to be charged to expense in current and future periods. Past service cost was calculated by determining the present value of the amount of future benefits accruing to the current employee group. Before APB Opinion No. 8 was issued, many companies charged past service costs against retained earnings as prior period adjustments. This policy was based on the theory that the benefits of employee service had been obtained in prior periods; therefore, the cost associated with those benefits should be charged to previous periods. APB Opinion No. 8 eliminated this treatment of past service costs, and later pronouncements concurred.
Prior Service Cost
Prior service costs were pension costs assigned to years preceding the date of a particular actuarial valuation. Prior service cost arose as a result of an amendment to the original pension agreement or changes in the actuarial assumptions of the pension plan. When the pension agreement is amended or the underlying assumptions change, it becomes necessary to recalculate the expected future ben- efits accruing to the current employee group. This calculation is similar to the determination of past service cost.
Actuarial Gains and Losses
The pension cost for any period is based on several assumptions. These assumptions often do not coincide with actual results. It is therefore necessary to make periodic adjustments so that actual experience is recognized in the recorded amount of pension expense. Under APB Opinion No. 8, periodic pension expense included normal cost and amortization of past and prior service costs. These costs were estimated based on actuarial assumptions. If in a subsequent period, the actuary revised his or her assumptions based on new information, a periodic adjustment would be required. APB Opinion No. 8 termed the deviations between the actuarial assumptions and subsequent changes in assumptions due to actual experience actuarial gains and losses.
The amount of any actuarial gain or loss was to be recognized over current and future periods by one of two acceptable methods:
1. Spreading. The net actuarial gains and losses were applied to current and future costs through an adjustment to either normal cost or past service cost each year.
2. Averaging. An average of the sum of previously expensed annual actuarial gains and losses and expected future actuarial gains and losses was applied to normal cost.
Basic Accounting Method
Before APB Opinion No. 8 was issued, the Board could not completely agree on the most appropriate measure of cost to be included in each period. Consequently, it
(Schroeder 491)
Schroeder, Richard G., Myrtle Clark, Jack Cathey. Financial Accounting Theory and Analysis: Text and Cases, 11th Edition. Wiley, 2013-11-04. VitalBook file.