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. 2021 Oct 8;11(10):e051574. doi: 10.1136/bmjopen-2021-051574

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© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.

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Flow of HAPPEN Study (exclusion process and data linkage). FSM, free school meal; HAPPEN, Health and Attainment of Pupils in a Primary Education Network; SAIL, Secure Anonymised Information Linkage.