performance-based contract rebates are most at risk for material adjustment because of the extensive time delay between the recording of the accrual and its ultimate settlement, an interval that can generally range up to one year. Because of this time lag, in any given quarter, our adjustments to actual can incorporate revisions of several prior quarters.

Asset Impairment Reviews

We review all of our long-lived assets for impairment indicators throughout the year. We perform impairment testing for indefinite-lived intangible assets and goodwill at least annually and for all other long-lived assets whenever impairment indicators are present. When necessary, we record charges for impairments of long-lived assets for the amount by which the fair value is less than the carrying value of these assets. Our impairment review processes are described in the Notes to Consolidated Financial Statements––Note 1K. Basis of Presentation and Significant Accounting Policies: Amortization of Intangible Assets, Depreciation and Certain Long-Lived Assets.

Examples of events or circumstances that may be indicative of impairment include:

• A significant adverse change in legal factors or in the business climate that could affect the value of the asset. For example, a successful challenge of our patent rights would likely result in generic competition earlier than expected.

• A significant adverse change in the extent or manner in which an asset is used. For example, restrictions imposed by the FDA or other regulatory authorities could affect our ability to manufacture or sell a product.

• A projection or forecast that indicates losses or reduced profits associated with an asset. This could result, for example, from a change in a government reimbursement program that results in an inability to sustain projected product revenues and profitability. This also could result from the introduction of a competitor’s product that results in a significant loss of market share or the inability to achieve the previously projected revenue growth, as well as the lack of acceptance of a product by patients, physicians and payers. For in-process research and development (IPR&D) projects, this could result from, among other things, a change in outlook based on clinical trial data, a delay in the projected launch date or additional expenditures to commercialize the product.

Identifiable Intangible Assets

As a result of our identifiable intangible asset impairment review work, we recognized a number of impairments of identifiable intangible assets for the years ended December 31, 2014, 2013 and 2012. See Notes to Consolidated Financial Statements––Note 4. Other (Income)/ Deductions—Net.

When we are required to determine the fair value of intangible assets other than goodwill, we use an income approach, specifically the discounted cash flow method. We start with a forecast of all the expected net cash flows associated with the asset, which includes the application of a terminal value for indefinite-lived assets, and then we apply an asset-specific discount rate to arrive at a net present value amount. Some of the more significant estimates and assumptions inherent in this