Measures of strategy flexibility in an abbreviated tri-phase test on linear and quadratic equation solving

This methodological paper is concerned with the issue of measuring strategy flexibility. We devised a 6-item tri-phase test from the domains of linear and quadratic equations. The test was completed by 306 students in an introductory university mathematics course. To validate the test we consider alternative definitions of key variables and conduct psychometric analyses of our strategy flexibility measures' internal consistency and factorial validity. We show that various choices for the definition of variables have no significant impact and that the test is internally consistent despite the inclusion of both linear and quadratic equations.