text: **Critical Accounting Estimates**
  Management makes judgments, estimates and assumptions that affect 
  how accounting policies are applied and the amounts we report in 
  assets, liabilities, revenue and expenses and our related disclosure about 
  contingent assets and liabilities. Significant changes in our assumptions, 
  including those related to our future business plans and cash flows, 
  could cause our actual results to be materially different. 
  We will change our depreciation methods, depreciation rates or asset 
  lives if they are determined to be different from our previous 
  useful 
  estimates. We recognize the effect of these changes in net income 
  prospectively. 
  
  **Capitalizing Direct Labour, Overhead and Interest**
  Certain direct labour and indirect costs associated with the acquisition, 
  construction, development or 
  improvements of our networks are 
  capitalized to property, plant and equipment. The capitalized amounts 
  are calculated based on estimated costs of projects that are capital in 
  nature, and are generally based on a rate per hour. In addition, interest 
  costs are capitalized during development and construction of certain 
  property, plant and equipment. Capitalized amounts increase the cost of 
  the asset and result in a higher depreciation expense in future periods. 
  
  **Fair Value**
  We use considerable judgment to estimate the fair value of tangible 
  and intangible assets acquired and liabilities assumed in an acquisition, 
  using the best available information including information from 
  financial markets. This may include discounted cash flow analyses which 
  utilize key assumptions such as discount rates, attrition rates, and 
  terminal growth rates to estimate future earnings. Actual results may 
  differ from these estimates. 