title: Ophthalmic statistics note 8: missing data--exploring the unknown.
authors.affiliation: Reserach & Development, NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London, UK.
authors.forename: Catey
authors.identifier: http://orcid.org/0000-0002-0935-3713
authors.initials: C
authors.lastname: Bunce
authors.affiliation: Reserach & Development, NIHR Biomedical Research Centre at Moorfields Eye Hospital NHS Foundation Trust and UCL Institute of Ophthalmology, London, UK.
authors.forename: Ana
authors.initials: A
authors.lastname: Quartilho
authors.affiliation: Department of Primary Care and Population Health, University College London, London, UK.
authors.forename: Nick
authors.initials: N
authors.lastname: Freemantle
authors.affiliation: UCL Comprehensive Clinical Trials Unit, University College London, London, UK.
authors.forename: Caroline J
authors.initials: CJ
authors.lastname: Doré
mesh_terms: D035843:Biomedical Research; D056808:Biostatistics / Q000379:methods*; D003627:Data Interpretation, Statistical; D006801:Humans; D009885:Ophthalmology / Q000706:statistics & numerical data*
keywords: Clinical Trial; Epidemiology; Medical Education; Vision