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Considering the efficacy of web-based worked examples in introductory chemistry.

Article Excerpt
Theory suggests that studying worked examples and engaging in self-explanation will improve learning and problem solving. A growing body of evidence supports the use of web-based assessments for improving undergraduate performance in traditional large enrollment courses. This article describes a study designed to investigate these techniques in a practical web-based setting. This study tracked introductory college chemistry students' use of a course quizzing system that provided both worked examples and strategy suggestions embedded within the quiz items. Student perceptions of the effectiveness of the enhancements were measured and correlated to use and performance. The findings indicate students made use of both the worked examples and self-explanation prompts, felt they were helpful, and the interventions improved performance.

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This study examined the potential for web-based worked examples and self-explanation strategies as part of a formative assessment system in introductory chemistry. The study is grounded in the literature on the use of worked examples and self-explanation strategies applied to a web-based repeatable testing environment. Theoretically, each strategy, considered separately, is well supported. This effort aimed to combine the three strategies in the chemistry domain in an effort to improve performance and problem-solving ability for undergraduate students in an introductory course.

The intent of this article is to: (a) provide a theoretical rationale, (b) describe our assessment system, (c) describe student use of the system, (d) report student response to the system, and (e) correlate student use with performance indicators. The reported data support the use of similar techniques for engaging students in using web-based worked examples and self-explanation prompts. Additional information regarding this study, including access to the assessment system and copies of our survey instruments, are available through the Web (http://crippen.nevada.edu/chemistry/WE_Study/).

THEORETICAL FRAMEWORK

Problem solving is an integral component of mathematics and science instruction (National Science Standards, 2003; Principles and Standards, 2003). Developing problem-solving ability is complex, however. Traditional approaches focus on teaching students algorithmic procedures and heuristic techniques. Algorithms are different from heuristics. Algorithms are a specific set of procedures that lead to a predefined outcome. In problem solving, algorithms always generate correct answers. Heuristics are collections of techniques or "rules of thumb" for developing a solution. Heuristics may contain algorithms.

The following is typical of traditional instruction in both science and math courses. The teacher presents a problem or concept by way of a problem. These problems are usually well-structured, multi-step in nature, require conceptual and procedural knowledge, and are presented with a model answer. The teacher articulates and models a solution algorithm or heuristic to aid students in solving similar problems. The teacher's presentation is followed shortly with an opportunity for students to practice the problem solving demonstrated in the form of an assignment. The assignment likely includes multiple versions of similar problems. The students are left to their own devices to complete the assignment, often times with some of the problem solutions provided by the back of their textbook.

While these strategies may be successful on some level, they certainly are not efficient. Learning and reiterating an algorithm or heuristic should not be confused with understanding a concept or possessing problem-solving ability. Traditional approaches that focus on skill instruction followed by voluminous practice tend to be lacking in skill transfer, conceptual understanding, and improvement in problem-solving ability (Pressley & McCormick, 1995). Additionally, research suggests that worked examples are more appropriate for inexperienced learners while problem-solving practice is more appropriate for experienced students (Kalyuga, Chandler, Tuovinen, & Sweller, 2001).

We conjecture that providing worked examples and self-explanation prompts within test items in a web-based repeatable testing environment has the potential to improve problem-solving ability and conceptual understanding. This is accomplished by giving students the opportunity to develop their own problem-solving strategies as a result of focusing their attention on problem states and problem-solving operators.

Worked Examples

Worked examples are detailed problem solutions that contain identifiable qualities and characteristics (Ward & Sweller, 1990). These representations are constructed in such a way as to provide the learner with some structure for understanding how the solution was established without providing a script or algorithm (Atkinson, Derry, Renkl, & Wortham, 2000). Depending upon the topic area, these solutions can take many forms. Snippets of computer program code can be effective worked examples for computer programming while structural...

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