Duane J. Jarc
The George Washington University
Department of Electrical Engineering and Computer Science
Washington, DC 20052
1. Problem and motivation
Computer-assisted instruction has been used for several decades, but the development of the new multimedia technology and the possibility of creating courseware that can be accessed by students worldwide by hosting it on the World Wide Web presents exciting new opportunities for educators. Before investing considerable time and effort building such multimedia courseware, it is important to determine the effectiveness of such materials and how they can be designed and used most effectively.
The animation of algorithms is one of the most obvious applications of this technology. Intuitively most computer science educators believe that algorithm animation should be helpful in teaching computer science concepts. The research that has attempted to determine whether it improves student learning has surprisingly been rather mixed. Some studies  have shown that student involvement improves the benefit of animation. One goal of our study is to determine whether providing a high level of interactivity improves student performance.
A second goal of our study is to determine whether there is a difference in the benefit provided by our multimedia courseware between students who have an active learning style compared to those with a reflective style as measured by the Felder-Silverman learning style model .
In our study, we use courseware that is hosted on the World Wide Web. This courseware incorporates algorithm animation and data structure visualization in a highly interactive multimedia environment. It is designed as laboratory assignments to be used during a four week period of a typical second semester computer science course in elementary data structures--often referred to as the CS 2 course.
It is our hope that this study will add to the important field of investigation that helps us understand how to effectively incorporate the rapidly changing technology into the field of education--computer science education, in particular.
2. Background and related work
Although much research has been done in solving the technical aspects of algorithm animation, less research has been done to assess whether it is really an effective tool in computer science education.
The first truly empirical study of algorithm animation was conducted by Stasko, Badre and Lewis . Although their overall results did not suggest that animation helped significantly, they noted that the animation seemed to help more on the declarative and analytical questions, but not on the procedural questions. In a subsequent study by Lawrence, Badre, and Stasko  a minimum spanning tree algorithm was used. They found that viewing animations in either a classroom or laboratory setting did not significantly improve students' understanding, however, those participating in an active laboratory setting performed significantly better than those who participated in a passive laboratory. The animation of sorting and searching algorithms was the subject of a study by Crosby and Stelovsky . They divided students into two groups according to their cognitive learning style as measured by their Myers-Briggs Type Indicator. Their results indicated that students categorized as sensing were helped significantly by animation, while the other group of students did not gain nearly the same level of benefit from the animation.
3. Approach and Uniqueness
The cornerstone of this research study is courseware entitled Interactive Data Structure Visualizations developed during the spring of 1997 by the author. This Web-based courseware focuses on several key areas in the typical introductory data structures course. The subject areas included are binary trees, graphs and sorting. Its current Web address is www.seas.gwu.edu/student/jarc/idsv.
The adjective interactive is included in its title because each segment allows students to be shown solutions with its Show Me mode and also to interact with the system in the I'll Try mode. It is the interactive capability supplied buy the I'll Try mode that separates this courseware from most other algorithm animation software. It allows students to repeat the steps of the algorithm after watching the animation to ensure their understanding of how the algorithm works.
This courseware was used in CSci 131, Data Structures, at The George Washington University during the spring 1997 in a preliminary trial. Browser problems prevented student from using it extensively. A subsequent evaluation by students recommended that it be incorporated as homework assignments for the course. During the current, fall 1997 semester, students are using it in this fashion. This pilot study was intended to ensure the usability of the courseware and to determine and correct any problems. During the spring 1998 semester the actual study was conducted. In that study the learning style of students was measured and the I'll Try mode was provided to half the students each week in the computer laboratory. The groups receiving the I'll Try mode were rotated during the four week study. The results of that study showed no significant differences. A redesigned study is currently being run. In this study, quizzes directly following the computer laboratory are being given as posttests rather than the using the final examination as had been done in the spring 1998 semester.
4. Results and Contributions
The demand for multimedia courseware, particular courseware accessible from the World Wide Web, seems likely to increase dramatically in the near future. It is important to know how such courseware can be made most effective. Studies have been done to measure the effectiveness of algorithm animation with mixed results. In our study we use both visualization of data structures and algorithm animation incorporated into a highly interactive courseware environment. It is our hope to determine whether adding interactivity can increase the benefit of algorithm animation. In addition we hope to determine whether the learning style of students influences the amount of benefit they gain from using the courseware. In the field of educational technology, many studies are needed before any question can be answered definitively. We hope that our study will make a contribution to this need.
Duane J. Jarc has been teaching computer science full-time for the past twelve years. He spent ten years at the University of Maryland University College, two years at Prince George's Community College and currently is an assistant professor at Northern Virginia Community College. He expects to complete his doctor of science degree at The George Washington University in the spring of 1999.