Instructional conceptions are students' ideas about relationships between instructional features of a learning environment or specific instructional interventions on the one hand, and learning on the other (Lowyck, Elen, & Clarebout, 2004). A variety of methods have been used to assess such conceptions. None of these instruments are satisfactory. In this contribution, problems with previously used instruments are discussed. A new instrument, namely a construction task assessing students' proceduralized conceptions, is proposed and tested. (Contains 3 figures, 1 table and 2 notes.)