Expansion and Evaluation of a Step-based Tutorial Program for Linear Circuit Analysis
Brian J. Skromme, Paul Rayes, Bing Cheng, Brian McNamara, Aaron Gibson, Angela Barrus, John M. Quick, Robert Atkinson, Yih-Fang Huang, Daniel H. Robinson · 2020
Abstract Expansion and Evaluation of a Step-Based Tutorial Program for Linear Circuit AnalysisComputer-aided instructional methods offer the possibility to allow students to work individuallyat their own pace, receiving feedback customized to their needs. Step-based tutorial systems, inwhich each step of a student’s work is input and immediately evaluated, are known to besignificantly more effective than traditional answer-based systems that only check thecorrectness of a final answer. Previously, we described the initial development of such a systemfor linear circuit analysis, in which automated algorithms are used to generate an unlimitedsupply of topologically different circuits of selected complexity as well as fully worked, error-free solutions to those exercises. The system accepts and evaluates student input in the form ofequations (entered using a template-based system to guide students), re-drawn circuit diagrams(using a drawing interface), simplified systems of equations, matrix equations, numericalanswers, and waveform sketches (entered using a specially designed drawing interface). Specialpedagogical features such as color coding are included to highlight concepts to students. Atutorial authoring system allows instructors to specify the ways in which sequences of problems,exercises, and expository material are presented to the student. Web-based exercises are used toprovide specific practice on unit conversions and complex number manipulation, two essentialskills in this course. Here, we describe the expansion of this system to cover a broader range oftopics in typical introductory circuit analysis courses. We further discuss the testing of thesystem both in a laboratory-based setting and in live classes, involving over 15 large sections ofa linear circuits class at our institution over several semesters and initial results in classes at threepartner institutions involving a diverse range of student characteristics. All student activity inthe system is logged to a central server, where it is available for later download and analysis.Instructors and administrators have a web-based portal where they can monitor student progress.The laboratory experiments involved a controlled, randomized trial in which we compared theeffectiveness of our system using a pre- and post-test for both a qualitative and quantitative topicto the traditional method of textbook-based problem solving. Students assigned to solveconventional problems increased their test scores by an average of 2.9/100 points, from 58.6 to61.6%, whereas the software users increased by 28.6 points, from 57.8 to 86.4%, a roughly 10Ximprovement. The statistically significant effect size (Cohen d-value) was 1.21 pooled standarddeviations, a very large effect. The Instructional Materials Motivation Survey of Keller wasadministered to both groups, showing a significant 0.53 point higher average for the softwareusers. In classroom use, about 99% of students rated the tutorials as either “very useful” or“somewhat useful” for learning the material, with over 74% considering them “very useful.”Student comments were generally very favorable, with students praising their ability to receiveunlimited practice with no penalty for wrong answers. They appreciated the confidence-buildingaspects of the software as well as the efficiency with which the rapid feedback helped them learnthe material.Fig. 1. Display of successfully entered simplified node equations and corresponding matrixequation. Highlighting of a selected KCL equation and labeling of the currents leaving aselected supernode with arrows that are color-coded to match the color of each term in theequation is also illustrated.Fig. 2. Screen shot of the prototype web-based equation sketching interface, showing apiecewise function that is being entered (and displayed below it).