title: The trouble with validity: what is part of it and what is not?
authors.affiliation: Hamburg, Germany.
authors.forename: Mirjana
authors.initials: M
authors.lastname: Knorr
authors.affiliation: Hamburg, Germany.
authors.forename: Dietrich
authors.initials: D
authors.lastname: Klusmann
mesh_terms: D004521:Educational Measurement / Q000592:standards*; D006801:Humans; D054928:Validation Studies as Topic