operating results and growth rates before and after the effect of currency changes. 

In addition, the remeasurement of our 6.875% PEACS and intercompany balances can result in significant gains and charges associated with the effect of movements in currency exchange rates. Currency volatilities may continue, which may significantly impact (either positively or negatively) our reported results and consolidated trends and comparisons. 

For additional information about each line item summarized above, refer to Item 8 of Part II, “Financial Statements and Supplementary Data—Note 1—Description of Business and Accounting Policies.” 

Critical Accounting Judgments 

The preparation of financial statements in conformity with generally accepted accounting principles of the United States (“GAAP”) requires estimates and assumptions that affect the reported amounts of assets and liabilities, revenues and expenses, and related disclosures of contingent assets and liabilities in the consolidated financial statements and accompanying notes. The SEC has defined a company’s critical accounting policies as the ones that are most important to the portrayal of the company’s financial condition and results of operations, and which require the company to make its most difficult and subjective judgments, often as a result of the need to make estimates of matters that are inherently uncertain. Based on this definition, we have identified the critical accounting policies and judgments addressed below. We also have other key accounting policies, which involve the use of estimates, judgments, and assumptions that are significant to understanding our results. For additional information, see Item 8 of Part II, “Financial Statements and Supplementary Data—Note 1—Description of Business and Accounting Policies.” Although we believe that our estimates, assumptions, and judgments are reasonable, they are based upon information presently available. Actual results may differ significantly from these estimates under different assumptions, judgments, or conditions. 

Revenue Recognition 

We recognize revenue from product sales or services rendered when the following four revenue recognition criteria are met: persuasive evidence of an arrangement exists, delivery has occurred or services have been rendered, the selling price is fixed or determinable, and collectability is reasonably assured. Additionally, revenue arrangements with multiple deliverables are divided into separate units of accounting if the deliverables in the arrangement meet the following criteria: the delivered item has value to the customer on a standalone basis; there is objective and reliable evidence of the fair value of undelivered items; and delivery of any undelivered item is probable. 

We evaluate the criteria of Emerging Issues Task Force (EITF) Issue No. 99-19, Reporting Revenue Gross as a Principal Versus Net as an Agent, in determining whether it is appropriate to record the gross amount of product sales and related costs or the net amount earned as commissions. Generally, when we are the primary party obligated in a transaction, are subject to inventory risk, have latitude in establishing prices