entry, as well as expected changes in standards of practice for indications addressed by the asset.

Determining the useful life of an intangible asset also requires judgment, as different types of intangible assets will have different useful lives and certain assets may even be considered to have indefinite useful lives. For example, the useful life of the right associated with a pharmaceutical product’s exclusive patent will be finite and will result in amortization expense being recorded in our results of operations over a determinable period. However, the useful life associated with a brand that has no patent protection but that retains, and is expected to retain, a distinct market identity could be considered to be indefinite and the asset would not be amortized.

Revenues

Revenue Recognition—We record revenues from product sales when the goods are shipped and title passes to the customer. At the time of sale, we also record estimates for a variety of sales deductions, such as rebates, discounts and incentives, and product returns. When we cannot reasonably estimate the amount of future product returns, we record revenue when the risk of product return has been substantially eliminated.

Deductions from Revenues—Our gross product sales are subject to a variety of deductions, primarily representing rebates and discounts to government agencies, wholesalers and managed care organizations with respect to our pharmaceutical products. These deductions represent estimates of the related obligations and, as such, judgment is required when estimating the impact of these sales deductions on gross sales for a reporting period.

Specifically:

• In the U.S., we record provisions for pharmaceutical Medicaid, Medicare and contract rebates based upon our actual experience ratio of rebates paid and actual prescriptions written during prior quarters. We apply the experience ratio to the respective period’s sales to determine the rebate accrual and related expense. This experience ratio is evaluated regularly to ensure that the historical trends are as current as practicable. As appropriate, we will adjust the ratio to better match our current experience or our expected future experience. In assessing this ratio, we consider current contract terms, such as changes in formulary status and discount rates. If our ratio is not indicative of future experience, our results could be materially affected.

• Outside the U.S., the majority of our pharmaceutical rebates are contractual or legislatively mandated, and our estimates are based on actual invoiced sales within each period; both of these elements help to reduce the risk of variations in the estimation process. Some European countries base their rebates on the government’s unbudgeted pharmaceutical spending and we use an estimated allocation factor against our actual invoiced sales to project the expected level of reimbursement. We obtain third-party information that helps us monitor the adequacy of these accruals. If our estimates are not indicative of actual unbudgeted spending, our results could be materially affected.

• Provisions for pharmaceutical chargebacks (primarily reimbursements to