The Modeling Assessment for Physics Laboratory Experiments (MAPLE) is an assessment that has been developed to measure students' processes of modeling in advanced-level lab classes focusing on either electronics or optics. The assessment consists of two surveys: a pre-test on mechanics (measuring the acceleration due to gravity using a pendulum) and a post-test on either an inverting amplifier circuit or a polarizer setup. In the figure on this page, we show some results from an initial analysis of the pendulum activity showing how students may have used different criteria to determine when their measured value for the acceleration due to gravity was "good enough" for them to stop the process of modeling.