pronouncements related to our indefinite-lived intangible assets impairment review. The new accounting guidance allows an entity to first assess qualitative factors to determine if it is more likely than not that the fair value of an indefinite-lived intangible asset unit is less than its carrying amount. In fiscal 2012, we used this new guidance in our annual impairment review. As a result of the review performed in the fourth quarter of fiscal 2012, we determined that there was no impairment of our goodwill and intangible assets as of September 30, 2012. The fair value of our restricted stock and restricted stock unit awards represents the closing price of our common stock on the date of award. Accounting for Income Taxes Current income taxes are determined based on estimated taxes payable or refundable on tax returns for the current year. Deferred income taxes are determined using enacted tax rates for the effect of temporary differences between the book and tax bases of recorded assets and liabilities. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. Provisions are made for both U.S. and any foreign deferred income tax liability or benefit. We recognize the tax benefit of an uncertain tax position only if it is more likely than not that the tax position will be sustained by the taxing authorities, based on the technical merits of the position. In fiscal 2012, 2011 and 2010, we elected to permanently reinvest the earnings of certain of our foreign subsidiaries outside the U.S. rather than repatriating the earnings to the U.S. See the section titled “Liquidity and Capital Resources” in this MD&A and Note 15 of the Notes to the Consolidated Financial Statements for additional information on income taxes and permanent reinvestment. Share-Based Compensation We record share-based compensation expense for all share-based awards, including stock option grants, restricted stock and restricted stock unit awards and employee stock purchases. We calculate share-based compensation expense using the straight-line approach based on awards ultimately expected to vest, which requires the use of an estimated forfeiture rate. Our estimated forfeiture rate is primarily based on historical experience, but may be revised in future periods if actual forfeitures differ from the estimate. We use the Black-Scholes option-pricing model to estimate the grant date fair value of our stock options and employee stock purchase plan purchases. This model requires the input of highly subjective assumptions, including the price volatility of the underlying stock, the expected term of our stock options and the risk-free interest rate. We estimate the expected volatility of our stock options based on a combination of our stock’s historical volatility and the implied volatilities from actively-traded options on our stock. Prior to fiscal 2012, we calculated the expected term of our stock options using the simplified method, due to our limited amount of historical option exercise data, and we added a slight premium to this expected term for employees who meet the definition of retirement eligible pursuant to their grants during the contractual term of the grant. The simplified method uses an average of the vesting term and the contractual term of the option to calculate the expected term. We experienced a significant increase in the volume of stock option exercises in fiscal 2011. Consequently, we used this exercise data, as well as historical exercise data, to calculate the expected term of our stock options granted in fiscal 2012, rather than using the simplified method, and we continued to add a slight premium for employees who meet the definition of retirement eligible under their grant terms. The expected term we calculated using option exercise history was within 1% of the expected term calculated under the simplified method. The risk-free rate is derived from the U.S. Treasury yield curve in effect at the time of grant. Commitments and Contingencies We have entered into certain unconditional purchase obligations, which include noncancelable purchase commitments and take-or-pay arrangements with suppliers. We review our agreements on a quarterly basis and make an assessment of the likelihood of a shortfall in purchases and determine if it is necessary to record a liability. In addition, we are subject to the possibility of various loss contingencies arising in the ordinary course of business such as a legal proceeding or claim. An estimated loss contingency is accrued when it is probable that an asset has been impaired or a liability has been incurred and the amount of the loss can be reasonably estimated. We regularly evaluate current information available to us to determine whether such accruals should be adjusted and whether new accruals are required. Effects of Recent Accounting Pronouncements See Note 2 to the Consolidated Financial Statements for a description of recent accounting pronouncements including the expected dates of adoption and effects on our results of operations, financial position and cash flows. 25