(dollars in millions)
(dollars in millions)
Years Ended December 31,
2019
2018
Consolidated Net Income
$19,788
$16,039
Add:
Provision for income taxes
2,945
3,584
Interest expense
4,730
4,833
Depreciation and amortization expense
16,682
17,403
Consolidated EBITDA
44,145
41,859
Add (Less):
Other (income) expense, net†
2,900
(2,364)
Equity in losses of unconsolidated businesses‡
15
186
Severance charges
204
2,157
Acquisition and integration related charges§
—
531
Product realignment charges§
—
450
Impairment charges
186
4,591
Net gain from dispositions of assets and businesses
(261)
—
Consolidated Adjusted EBITDA
$ 47,189
$ 47,410
consolidated net income consolidated ebitda and consolidated adjusted ebitda .
consolidated earnings before interest taxes depreciation and amortization expenses -consolidated ebitda and consolidated adjusted ebitda which are presented below are non-generally accepted accounting principles -gaap measures that we believe are useful to management investors and other users of our financial information in evaluating operating profitability on a more variable cost basis as they exclude the depreciation and amortization expense related primarily to capital expenditures and acquisitions that occurred in prior years .
as well as in evaluating operating performance in relation to verizon ’ s competitors .
consolidated ebitda is calculated by adding back interest taxes and depreciation and amortization expenses to net income .
consolidated adjusted ebitda is calculated by excluding from consolidated ebitda the effect of the following non-operational items : equity in losses of unconsolidated businesses and other income and expense net as well as the effect of special items .
we believe that this measure is useful to management investors and other users of our financial information in evaluating the effectiveness of our operations and underlying business trends in a manner that is consistent with management ’ s evaluation of business performance .
we believe that consolidated adjusted ebitda is widely used by investors to compare a company ’ s operating performance to its competitors by minimizing impacts caused by differences in capital structure taxes and depreciation policies .
further the exclusion of non-operational items and special items enables comparability to prior period performance and trend analysis .
see “ special items ” for additional information .
it is management ’ s intent to provide non-gaap financial information to enhance the understanding of verizon ’ s gaap financial information and it should be considered by the reader in addition to but not instead of the financial statements prepared in accordance with gaap .
each non-gaap financial measure is presented along with the corresponding gaap measure so as not to imply that more emphasis should be placed on the non-gaap measure .
we believe that non-gaap measures provide relevant and useful information which is used by management investors and other users of our financial information as well as by our management in assessing both consolidated and segment performance .
the non-gaap financial information presented may be determined or calculated differently by other companies and may not be directly comparable to that of other companies .
† includes pension and benefits mark-to-market adjustments and early debt redemption costs where applicable .
‡ includes product realignment charges and impairment charges where applicable .
§ excludes depreciation and amortization expense .
the changes in consolidated net income consolidated ebitda and consolidated adjusted ebitda in the table above were primarily a result of the factors described in connection with operating revenues and operating expenses .

Question: Why is Consolidated Adjusted EBITDA useful?
Answer: evaluating the effectiveness of our operations and underlying business trends in a manner that is consistent with management’s evaluation of business performance.