from that which is reflected in our historical income tax provisions and accruals. Such differences could have a material effect on our income tax provision and net income in the period in which such determination is made.

 

Our effective tax rate includes the impact of certain undistributed foreign earnings for which no U.S. taxes have been provided because such earnings are planned to be indefinitely reinvested outside the United States.

 

Remittances of foreign earnings to the U.S. are planned based on projected cash flow, working capital and investment needs of foreign and domestic operations. Based on these assumptions, we estimate the amount that will be distributed to the U.S. and provide U.S. federal taxes on these amounts. Material changes in our estimates could impact our effective tax rate.

 

We record a valuation allowance to reduce our deferred tax assets to the amount that is more likely than not to be realized. In order for us to realize our deferred tax assets, we must be able to generate sufficient taxable income in those jurisdictions where the deferred tax assets are located. We consider future market growth, forecasted earnings, future taxable income, the mix of earnings in the jurisdictions in which we operate and prudent and feasible tax planning strategies in determining the need for a valuation allowance. In the event we were to determine that we would not be able to realize all or part of our net deferred tax assets in the future, an adjustment to the deferred tax assets would be charged to earnings in the period in which we make such determination. Likewise, if we later determine that it is more likely than not that the net deferred tax assets would be realized, we would reverse the applicable portion of the previously provided valuation allowance.

 

We calculate our current and deferred tax provision based on estimates and assumptions that could differ from the actual results reflected in income tax returns filed during the subsequent year. Adjustments based on filed returns are generally recorded in the period when the tax returns are filed and the global tax implications are known.

 

The amount of income tax we pay is subject to ongoing audits by federal, state and foreign tax authorities, which often result in proposed assessments. Our estimate of the potential outcome for any uncertain tax issue is highly judgmental. We believe we have adequately provided for any reasonably foreseeable outcome related to these matters. However, our future results may include favorable or unfavorable adjustments to our estimated tax liabilities in the period the assessments are made or resolved, audits are closed or when statutes of limitation on potential assessments expire. Additionally, the jurisdictions in which our earnings or deductions are realized may differ from our current estimates. As a result, our effective tax rate may fluctuate significantly on a quarterly basis.

 

As part of our accounting for business combinations, some of the purchase price is allocated to goodwill and intangible assets. Impairment charges associated with goodwill are generally not tax deductible and will result in an increased