- Ratio of orders booked to revenue in the period.
- Before exceptional items, acquired intangible asset amortisation and share-based payment.
- Adjusted operating profit as a percentage of revenue in the period.
- Adjusted basic earnings per share is based on adjusted earnings as set out in note 11 of Notes to the full year consolidated financial statements.
- Operating cash flow after tax, net interest and net capital expenditure.
Items with notes 1 to 5 above are non-GAAP alternative performance measures, see pages 182 and 183 of the Spirent Communications plc Annual Report 2018 for more detail.