title: Editorial authors' reply to Barlow.
authors.affiliation: Department of Public Health and Policy, University of Liverpool, Liverpool L69 3GB, UK.
authors.forename: Ben
authors.initials: B
authors.lastname: Barr
authors.affiliation: Department of Public Health and Policy, The Farr Institute@HeRC, Liverpool, UK.
authors.forename: David
authors.initials: D
authors.lastname: Taylor-Robinson