we generally use the “market approach,” where we compare the segment to similar businesses or “guideline” companies whose securities are actively traded in public markets or which recently have been sold in a private transaction. Within the Diversified business, we generally use the “income approach,” where we use a discounted cash flow model in which cash flows anticipated over several periods, plus a terminal value at the end of that time horizon, are discounted to their present value using an appropriate rate of return. Some of the more significant estimates and assumptions inherent in the goodwill impairment estimation process using the “market approach” include: the selection of appropriate guideline companies; the determination of market value multiples for the guideline companies and the subsequent selection of an appropriate market value multiple for the business based on a comparison of the business to the guideline companies; and the determination of applicable premiums and discounts based on any differences in ownership percentages, ownership rights, business ownership forms or marketability between the segment and the guideline companies; and/or knowledge of the terms and conditions of comparable transactions. When considering the “income approach,” we include the required rate of return used in the discounted cash flow method, which reflects capital market conditions and the specific risks associated with the business. Other estimates inherent in the “income approach” include long-term growth rates and cash flow forecasts for the business. The long-term growth rate and cash flow forecasts are derived from expected sales of our commercial products and are subject to inherent uncertainties such as decisions by regulatory authorities regarding labeling and other matters that could affect the sales of our products, among other factors.

A single estimate of fair value results from a complex series of judgments about future events and uncertainties and relies heavily on estimates and assumptions (see the “Estimates and Assumptions” section of this Financial Review). The judgments made in determining an estimate of fair value can materially impact our results of operations.

Pension and Postretirement Benefit Plans

We provide defined benefit pension plans for the majority of our employees worldwide. In the U.S., we have both qualified and supplemental (non-qualified) defined benefit plans, as well as other postretirement benefit plans, consisting primarily of healthcare and life insurance for retirees (see Notes to Consolidated Financial Statements—Note 13. Pension and Postretirement Benefit Plans and Defined Contribution Plans).

The accounting for benefit plans is highly dependent on actuarial estimates, assumptions and calculations, which result from a complex series of judgments about future events and uncertainties (see the “Estimates and Assumptions” section of this Financial Review). The assumptions and actuarial estimates required to estimate the employee benefit obligations for the defined benefit and postretirement plans may include the discount rate; expected salary increases; certain employee-related factors, such as