We believe the non-IFRS measures we present herein are useful, as they enable investors to evaluate and compare our results from operations and cash resources generated from our business in a more consistent manner (by excluding specific items that we do not consider to be reflective of our ongoing operating results) and provide an analysis of operating results using the same measures our chief operating decision makers use to measure performance. The non-IFRS financial measures that can be reconciled to IFRS measures result largely from management's determination that the facts and circumstances surrounding the excluded charges or recoveries are not indicative of the ordinary course of our ongoing operation of our business.

Non-IFRS measures do not have any standardized meaning prescribed by IFRS and may not be comparable to similar measures presented by other public companies that use IFRS, or who report under U.S. GAAP and use non-U.S. GAAP measures to describe similar operating metrics. Non-IFRS measures are not measures of performance under IFRS and should not be considered in isolation or as a substitute for any standardized measure under IFRS. The most significant limitation to management's use of non-IFRS financial measures is that the charges or credits excluded from the non-IFRS measures are nonetheless charges or credits that are recognized under IFRS and that have an economic impact on the company. Management compensates for these limitations primarily by issuing IFRS results to show a complete picture of the company's performance, and reconciling non-IFRS results back to IFRS results where a comparable IFRS measure exists.

The economic substance of these exclusions and management's rationale for excluding these from non-IFRS financial measures is provided below:

Employee stock-based compensation expense, which represents the estimated fair value of stock options, restricted share units and performance share units granted to employees, is excluded because grant activities vary significantly from quarter-to-quarter in both quantity and fair value. In addition, excluding this expense allows us to better compare core operating results with those of our competitors who also generally exclude employee stock-based compensation expense from their core operating results, who may have different granting patterns and types of equity awards, and who may use different valuation assumptions than we do, including those competitors who use U.S. GAAP and non-U.S. GAAP measures to present similar metrics.

Amortization charges (excluding computer software) consist of non-cash charges against intangible assets that are impacted by the timing and magnitude of acquired businesses. Amortization of intangible assets varies among our competitors, and we believe that excluding these charges permits a better comparison of core operating results with those of our competitors who also generally exclude amortization charges.

Restructuring and other charges, net of recoveries, include costs relating to employee severance, lease terminations, facility closings and consolidations, write-downs of owned property and equipment which are no longer used and are available for sale, reductions in infrastructure and acquisition-related transaction costs. We exclude restructuring and other charges, net of recoveries, because we believe that they are not directly related to ongoing operating results and do not reflect expected future operating expenses after completion of these activities.  We believe these exclusions permit a better comparison of our core operating results with those of our competitors who also generally exclude these charges, net of recoveries, in assessing operating performance.

Impairment charges, which consist of non-cash charges against goodwill, intangible assets and property, plant and equipment, result primarily when the carrying value of these assets exceeds their recoverable amount. Our competitors may record impairment charges at different times. We believe that excluding these charges permits a better comparison of our core operating results with those of our competitors who also generally exclude these charges in assessing operating performance.

Gains or losses related to the repurchase of shares or debt are excluded as these gains or losses do not impact core operating performance and vary significantly among those of our competitors who also generally exclude these charges or recoveries in assessing operating performance.

Significant deferred tax write-offs or recoveries associated with restructuring actions or restructured sites are excluded as these write-offs or recoveries do not impact core operating performance and vary significantly among those of our competitors who also generally exclude these charges or recoveries in assessing operating performance.

The following table sets forth, for the periods indicated, the various non-IFRS measures discussed above, and a reconciliation of IFRS to non-IFRS measures, where a comparable IFRS measure exists (in millions, except percentages and per share amounts):