title: Mathematical coupling: a simpler approach.
authors.affiliation: Institute of Education, 20 Bedford Way, London, WC1H 0AL, UK. j.rabash@ioe.ac.uk
authors.forename: Jon
authors.initials: J
authors.lastname: Rasbash
authors.forename: Harvey
authors.initials: H
authors.lastname: Goldstein
mesh_terms: D015982:Bias; D006801:Humans; D008433:Mathematics; D015233:Models, Statistical