5.	Costs of services and general and administrative costs


	Six months ended 30 June 2018		Six months ended 30 June 2017¹		Year ended 31 December 2017¹
	£m		£m		£m
Costs of services		6,218.7		6,282.3		12,629.0
General and administrative costs		432.1		643.7		1,267.0
		6,650.8		6,926.0		13,896.0

Costs of services and general and administrative costs include:


	Six months ended 30 June 2018		Six months ended 30 June 2017¹		Year ended 31 December 2017¹
	£m		£m		£m
Staff costs		4,032.6		4,177.0		8,319.0
Establishment costs		433.7		443.9		888.6
Media pass-through costs		740.9		701.6		1,429.4
Data collection pass-through costs		286.6		314.2		646.4
Other costs of services and general and administrative costs²		1,157.0		1,289.3		2,612.6
		6,650.8		6,926.0		13,896.0

Notes

¹	Prior year figures have been restated for the impact of the adoption of IFRS 15: Revenue from Contracts with Customers, as described in note 2.

²	Other costs of services and general and administrative costs include £316.3 million (period ended 30 June 2017: £258.5 million; year ended 31 December 2017: £558.8 million) of other pass-through costs.

Staff costs include:


	Six months ended 30 June 2018		Six months ended 30 June 2017		Year ended 31 December 2017
	£m		£m		£m
Wages and salaries		2,805.4		2,919.1		5,832.3
Cash-based incentive plans		74.1		53.8		219.2
Share-based incentive plans		41.6		50.6		105.0
Social security costs		367.7		370.2		720.3
Pension costs		93.1		97.2		192.0
Severance		16.8		34.5		39.5
Other staff costs		633.9		651.6		1,210.7
		4,032.6		4,177.0		8,319.0

Other costs of services and general and administrative costs include:


	Six months ended 30 June 2018			Six months ended 30 June 2017			Year ended 31 December 2017
	£m			£m			£m
Amortisation and impairment of acquired intangible assets		84.0			97.8			195.1
Goodwill impairment		—			—			27.1
Gains on disposal of investments and subsidiaries		(189.9	)		(5.9	)		(129.0	)
(Gains)/losses on remeasurement of equity interests arising from a change in scope of ownership		(0.1	)		0.2			0.3
Investment write-downs		1.5			—			95.9
Restructuring costs		45.5			19.2			56.8

In 2018, restructuring costs of £45.5 million (2017: £19.2 million) predominantly comprise severance costs arising from a structural reassessment of certain of the Group’s operations. In the year ended 31 December 2017, restructuring costs of £56.8 million predominantly comprise £33.7 million of severance costs and £12.8 million of costs resulting from the project to transform and rationalise the Group’s IT services and infrastructure, including costs relating to the cyber attack in June 2017.

Gains on disposal of investments and subsidiaries in 2018 include a gain of £185.3 million on the disposal of the Group’s interest in Globant S.A. Gains in the year ended 31 December 2017 include a gain of £92.3 million on the sale of the Group’s interest in Asatsu-DK Inc following its acquisition by Bain Capital.

Investment write-downs in the year ended 31 December 2017 includes £53.1 million in relation to comScore Inc, which had not released any financial statements in relation to its 2015, 2016 or 2017 results due to an internal investigation by their Audit Committee. In 2017, the market value of comScore Inc fell below the Group’s carrying value.