> 0164-SIP-2007-PIEEE < 1 Abstract— This paper reviews our work on providing students interactive access to annotated program examples. We review our experience with WebEx, the system that allows students to explore examples line by line. After that we present NavEx, an adaptive environment for accessing interactive programming examples. NavEx enhances WebEx with a specific kind of adaptive navigation support known as adaptive annotation. The classroom study of NavEx discovered that adaptive navigation support can visibly increase student motivation to work with non-mandatory educational content. NavEx boosted the overall amount of work done and the average length of a session. In addition, various features of NavEx were highly regarded by the students. Index Terms— Adaptive systems, Computer science education, Educational technology, Hypertext systems, Programming, User modeling I. INTRODUCTION ROBLEM-solving examples play an important role in teaching many engineering disciplines. In the area of teaching programming, program examples in the form of small meaningful programs help students to understand syntax, semantics and the pragmatics of programming languages, as well as to provide useful problem-solving cases. Experienced teachers of programming-related courses prepare several program examples for every lecture and spend a reasonable fraction of lecture time analyzing these examples. To let the students further explore these examples and use them as models for solving assigned problems, teachers often include the code from these examples in their handouts and may even make it accessible online. Unfortunately, these study tools are not a substitute for an interactive example presented during the lecture. While the example code is still there, the explanations are not. For the students who failed to understand the example in class or who missed the class, the power of the example is lost. The project presented in this paper attempted to solve this problem by offering the students an opportunity to explore programming examples as well as their explanations by using Manuscript received November 11, 2007. This work was supported in part by the University of Pittsburgh Innovation in Education Grant and by National Science Foundation under Grants OCI-0426021 and IIS-0447083. P. Brusilovsky is with the School of Information Sciences, University of Pittsburgh, PA 15260 USA (phone: 412-624-9404; fax: 412-624-2788; e-mail: peterb @ pitt.edi). M. Yudelson is with the School of Information Sciences, University of Pittsburgh, PA 15260 USA (e-mail: mvy3 @ pitt.edu). Web-based interactive tools outside of class. Over the course of the project we developed and evaluated two systems for Web-based access to examples – WebEx and NavEx. WebEx provided basic access to explained examples, while NavEx extended the power of WebEx by providing personalized guidance. This paper presents an account of our project. Sections II and III introduce WebEx and NavEx and review the students subjective feedback about the systems. Section IV compares these systems and examines the nature of the increased impact of NavEx. At the end we summarize the results and discuss our future research plans. II. WEBEX: EXPLORING ANNOTATED PROGRAM EXAMPLES A. The Motivation The goal of WebEx, a Web-based tool for exploring programming examples, was to turn explained examples into first class educational material that the students can explore anytime, anywhere and at their own pace. To achieve this goal, WebEx replaced the bare code of programming examples offered on the course Web site with interactive explained examples. This idea of explained examples was motivated by an approach to example explanations used in several programming textbooks and sometimes referred to as "dissections" [1]. In this approach, an author of an example supplies textual explanations for each important line in the example program. The explanations serve at least two different purposes. First, they explain the meaning of each program line and its role of in the overall solution of a programming problem. Second, the comments on a particular way of using language constructs in every line of code thus bridge the gap between student general knowledge about programming language constructs and the practical skills of their use for solving programming problems. In a typical programming textbook a dissected example is provided in a format where each line of code is followed by explanations (which can vary from a line or two to several paragraphs of text). This format has a clear problem: even in textbooks that use some special font and color for the lines of code, the code is hard to comprehend since the lines of code are spread over the explanations. The explanations are not easy to comprehend either. Usually, a student has a problem with just a few lines of code in a program and need explanations for just these lines. Presenting all explanations at once distracts the student from concentrating on the most needed explanations. Finally, reading through a large “dissection” is a rather passive kind of learning. From WebEx to NavEx: Interactive Access to Annotated Program Examples Peter Brusilovsky and Michael Yudelson P> 0164-SIP-2007-PIEEE < 2 B. The WebEx Interface WebEx, a Web-based tool for interactive exploration of programming examples, was designed to overcome the problems listed above. A program example in WebEx appears to be just the same as it looked in a program editor (Figure 1). The only visible difference is the presence of green or white navigation bullets to the left of each line. A green bullet indicates the availability of explanations for this line of code. A white bullet marks that there are no explanations for that line. Clicking on a green bullet opens an explanations note for the selected line. In the spirit of good hypertext, the WebEx interface lets the user use his or her preferred browsing strategy. Some users may choose to browse the example