Signals and systems assessment: Comparison of responses to multiple choice conceptual questions and open-ended final exam problems

The validity of the Signals and Systems Concept Inventory (SSCI) was evaluated by comparing students´ performance on the SSCI to open-ended final exam problems. An assessment instrument is said to be valid to the extent that it measures what it was designed to measure. The SSCI was designed to measure students´ understanding of core concepts in undergraduate signals and systems (S&S) courses through 25 multiple choice questions. The SSCI scores and final exam scores for more than 150 students in four sections of S&S at two schools were found to have a statistically significant correlation. A more detailed analysis was conducted with a pool of over 60 students at both schools. This second analysis compared detailed coding of students´ responses on the final exam problems to their answers for specific SSCI questions assessing the same topic. This analysis found statistically significant correlations between SSCI questions and final exam problems for some convolution and Fourier transform problems. Results were mixed for the problem on Bode plots.