Description: This paper examines tandem levels of salary and interest rates and finds that the absolute level of each assumption as well as the differential are significant cost determinants for defined benefit pension plans. In forming best-estimate salary and interest rate assumptions, the actuary must reconcile the difference, if any, between the currently observed rates and the valuation assumptions. Common practice is to choose expected long-term rather than observed rates for valuation purposes. The error in this procedure is analyzed and found to be tolerable for strictly temporary discrepancies between observed rates and valuation assumptions. For situations where these discrepancies are expected to persist for some time, a need is shown for nonuniform, calendar-year assumptions or their equivalent in order to develop best-estimate assumptions. Followed by several discussion papers submitted