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datto Non - GAAP Financial Measures In addition to our results determined in accordance with generally accepted accounting principles in the United States ( " GAAP " ) , we believe that the non - GAAP financial measures of Non - GAAP Subscription Cost of Revenue , Non - GAAP Device Cost of Revenue , Non - GAAP Professional Services and Other Cost of Revenue , Non - GAAP Depreciation and Amortization in Cost of Revenue , Non - GAAP Cost of Revenue , Non - GAAP Gross Profit , Non - GAAP Sales and Marketing expense , Non - GAAP Research and Development expense , Non - GAAP General and Administrative expense , Non - GAAP Depreciation and Amortization in Operating Expenses , Non - GAAP Operating Expenses , Non - GAAP Income from Operations , Non GAAP Net Income and Non - GAAP Net Income Per Share , Adjusted EBITDA , and Free Cash Flow are useful in evaluating our operating performance . Certain of these measures exclude interest and other ( income ) expense , net , loss on extinguishment of debt , depreciation and amortization , stock - based compensation expense , restructuring expense and transaction - related and other expense . In addition , for Non - GAAP Net Income we utilize a non - GAAP tax rate of 25 % , which we believe reflects our normalized effective tax rate . We believe that non - GAAP financial information , when taken collectively , may be helpful to investors because it provides consistency and comparability with past financial performance and assists in comparisons with other companies , some of which use similar non - GAAP financial information to supplement their GAAP results . The non - GAAP financial information is presented for supplemental informational purposes only , and should not be considered a substitute for financial information presented in accordance with GAAP , and may be different from similarly - titled non - GAAP measures used by other companies .