Year Ended December 31,
Year Ended December 31,
Year Ended December 31,
Year Ended December 31,
(IN MILLIONS)
2019
2018
2017
Net income/(loss) attributable to Nielsen shareholders
$(415)
$(712)
$429
Interest expense, net
391
386
370
(Benefit)/provision for income taxes
(260)
(182)
388
Depreciation and amortization
756
675
640
EBITDA
472
167
1,827
Other non-operating (income)/expense, net(b)
191
33
27
Restructuring charges
80
139
80
Impairment of goodwill and other long-lived assets
1,004
1,413
-
Share-based compensation expense
50
35
45
Other items(a)
56
63
45
Adjusted EBITDA
$1,853
$1,850
$2,024
net income to adjusted ebitda reconciliation .
we define adjusted ebitda as net income or loss from our consolidated statements of operations before interest income and expense income taxes depreciation and amortization restructuring charges impairment of goodwill and other long-lived assets share-based compensation expense and other nonoperating items from our consolidated statements of operations as well as certain other items considered outside the normal course of our operations specifically described below .
restructuring charges : we exclude restructuring expenses which primarily include employee severance office consolidation and contract termination charges from our adjusted ebitda to allow more accurate comparisons of the financial results to historical operations and forward-looking guidance .
by excluding these expenses from our non-gaap measures we are better able to evaluate our ability to utilize our existing assets and estimate the long-term value these assets will generate for us .
furthermore we believe that the adjustments of these items more closely correlate with the sustainability of our operating performance .
impairment of goodwill and other long-lived assets : we exclude the impact of charges related to the impairment of goodwill and other long-lived assets .
given the significance of the impairment of goodwill and other long-lived assets we reported it separately in the consolidated statements of operations .
we believe that the exclusion of these impairments which are non-cash allows for meaningful comparisons of operating results to peer companies .
we believe that this increases period-to-period comparability and is useful to evaluate the performance of the total company .
share-based compensation expense : we exclude the impact of costs relating to share-based compensation .
due to the subjective assumptions and a variety of award types we believe that the exclusion of share-based compensation expense which is typically non-cash allows for more meaningful comparisons of our operating results to peer companies .
share-based compensation expense can vary significantly based on the timing size and nature of awards granted .
other non-operating income / -expense net : we exclude foreign currency exchange transaction gains and losses primarily related to intercompany financing arrangements as well as other non-operating income and expense items such as gains and losses recorded on business combinations or dispositions sales of investments pension settlements net income / -loss attributable to noncontrolling interests and early redemption payments made in connection with debt refinancing .
we believe that the adjustments of these items more closely correlate with the sustainability of our operating performance .
other items : to measure operating performance we exclude certain expenses and gains that arise outside the ordinary course of our operations .
such costs primarily include legal settlements acquisition related expenses business optimization costs and other transactional costs .
we believe the exclusion of such amounts allows management and the users of the financial statements to better understand our financial results .
adjusted ebitda is not a presentation made in accordance with gaap and our use of the term adjusted ebitda may vary from the use of similarly titled measures by others in our industry due to the potential inconsistencies in the method of calculation and differences due to items subject to interpretation .
adjusted ebitda margin is adjusted ebitda for a particular period expressed as a percentage of revenues for that period .
we use adjusted ebitda to measure our performance from period to period both at the consolidated level as well as within our operating segments to evaluate and fund incentive compensation programs and to compare our results to those of our competitors .
in addition to adjusted ebitda being a significant measure of performance for management purposes we also believe that this presentation provides useful information to investors regarding financial and business trends related to our results of operations and that when non-gaap financial information is viewed with gaap financial information investors are provided with a more meaningful understanding of our ongoing operating performance .
adjusted ebitda should not be considered as an alternative to net income or loss operating income / -loss cash flows from operating activities or any other performance measures derived in accordance with gaap as measures of operating performance or cash flows as measures of liquidity .
adjusted ebitda has important limitations as an analytical tool and should not be considered in isolation or as a substitute for analysis of our results as reported under gaap .
in addition our definition of adjusted ebitda may not be comparable to similarly titled measures of other companies and may therefore have limitations as a comparative analytical tool .
the below table presents a reconciliation from net income / -loss to adjusted ebitda for the years ended december 31 2019 2018 and 2017 : .
-a for the years ended december 31 2019 and 2018 other items primarily consists of business optimization costs including strategic review costs and transaction related costs .
for the year ended december 31 2017 other items primarily consists of transaction related costs and business optimization costs .
-b for the year ended december 31 2019 other non-operating -income / expense net included non-cash expenses of $ 170 million for pension settlements which included plan transfers to third parties in the netherlands and uk where we terminated our responsibility for future defined benefit obligations and transferred that responsibility to the third parties .
see note 11 “ pensions and other post-retirement benefits ” for more information .

Question: How does share-based compensation expense vary?
Answer: based on the timing, size and nature of awards granted