title: Letter to the editor.
authors.affiliation: Centre for Statistics in Medicine, Botnar Research Centre, University of Oxford, Windmill Road, Oxford OX3 7LD, UK. Electronic address: gary.collins@csm.ox.ac.uk.
authors.forename: Gary S
authors.initials: GS
authors.lastname: Collins
mesh_terms: D020345:Enterocolitis, Necrotizing / Q000175:diagnosis*; D005260:Female; D006801:Humans; D007235:Infant, Premature, Diseases / Q000175:diagnosis*; D008297:Male; D012720:Severity of Illness Index