15 Setting up CS or PBL exercises Standard college textbook problems in science and other disciplines tend to reinforce the students' naive view of learning because they can successfully answer homework end-of-chapter problems through memorization of facts and equations and using novice "pattern-match" problem-solving techniques. Typical problems do not foster the development of effective problem-solving and analytical skills (Heller and Hollabaugh, 1992) nor do they challenge students to develop critical thinking skills and logical reasoning (Mazur, 1996). In a successful PBL course, the selection of appropriate problems and material is crucial for students to go beyond a superficial understanding of the important concepts and principles being taught. Characteristics of Good PBL Problems There may be more characteristics of good PBL problems than those listed below, and those characteristics may vary somewhat according to the discipline. However, many practitioners of problem-based instruction will probably identify the following as important characteristics of a good PBL problem:     1.    An effective problem must first engage students' interest, and motivate them to probe for deeper understanding of the concepts being introduced. It should relate the subject matter to the real world as much as possible.     2.    Problems that work well sometimes require students to make decisions or judgments based on facts, information, logic and/or rationalization. In this kind of problem, students will be asked to justify their decisions and reasoning based on the principles being learned. Problems may require students to decide what assumptions are needed (and why), what information is relevant, and/or what steps or procedures are required in order to solve the problem. Not all the information given in the problem needs to be relevant to a solution, as is the case in "messy" real world situations. And not all the information needed for a solution will be given to the student right away. For this reason, many PBL problems are designed with multiple stages, to be given to student groups one at a time, as they work through the problem. The second stage of the problem may give additional information to students related to issues raised in the first stage of the problem.     3.    The problem should be complex enough that cooperation from all members of the student group will be necessary in order for them to effectively work towards a solution. The length and complexity of the problem or case must be such that students soon realize that a "divide and conquer" effort will not be an effective problem-solving strategy. For example, a problem that consists of a series of straight-forward "end of chapter" questions will be divided by the group and assigned to individuals and then reassembled for the assignment submission. In this case, students end up learning less not more.     4.    The initial questions in the first stage of a problem should be open-ended, based on previously learned knowledge, and/or be controversial so that all students in the groups are initially drawn into a discussion of the topic. This strategy keeps the students functioning as a group, rather than encouraging them to work individually at the outset of the problem.     5.    The content objectives of the course should be incorporated into the problems, connecting previous knowledge to new concepts, and connecting new knowledge to concepts in other courses and/or disciplines. The problem's questions should challenge students to develop higher order thinking skills, moving them beyond Bloom's (1956) lower cognitive levels of knowledge and comprehension to the higher Bloom levels, where they analyze, synthesize and evaluate. These are the skills that are so important for our students to develop in order to succeed in any profession. Suggestions for Writing PBL Problems Finding good PBL problems is a challenge in most disciplines. They generally aren't found in traditional texts, so the search for material for a problem-based course takes a certain amount of creativity. Some faculty use video-clips, stories, novels, articles in the popular press, and research papers as the basis of a problem. Frequently, veteran PBL faculty may use a typical textbook problem, and rewrite it as an open-ended, real world problem. The process of developing a multi-stage PBL problem may differ from one discipline to another, but generally the steps shown below can help instructors write problems for any course.     1.    Choose a central idea, concept or principle that is always taught in a given course, and then think of a typical end-of-chapter problem, assignment, or homework that is usually assigned to students to help them learn that concept. List the learning objectives that students should meet when they work through the problem.     2.    Think of a real-world context for the concept under consideration. Develop a story-telling aspect to an end-of-chapter problem or research an actual case that can be adapted, adding some motivation for students to solve the problem. A complex, ill-structured problem will challenge students to go beyond simple "plug-and-chug" in order to solve it. Look at magazines, newspapers, and articles for ideas on the "story-line".     3.    The problem needs to be introduced and staged so that students will be able to identify learning issues that will lead them to research the targeted through the problem? Many times, PBL problems are designed as multi-stage or multi-page and may take student groups a week or more to complete. Not all the information needed to solve the problem is given in the problem, or chapter, or perhaps even in the textbook. Students will need to do some research, discover new material, arrive at judgments and decisions based on the information learned. The problem may have more than one acceptable answer, based on the assumptions students make.     4.    Write a teacher guide detailing the instructional plans on using the problem in the course. The teacher guide can indicate plans or options of cycling through the pages of the problem interspersing the various modes of learning.     5.    The final step is to identify resources for students. Students need to learn to identify and utilize learning resources on their own, but it can be helpful if the instructor indicates a few good sources to get them started. Many students today will want to limit their research to the internet, and so it will be important to guide them toward the library as well. Conclusion Writing problem-based learning problems may be time consuming, challenging, and sometimes frustrating. However, the process of thinking through the learning priorities of a course and finding, adapting, or writing complex, realistic materials to meet those learning priorities will change how an instructor views his or her course in the future. References Bloom, B.S. ed. (1956). Taxonomy of educational objectives: The classification of educational goals. New York: Longman. Heller, P., and Hollabaugh, M. (1992). Teaching problem-solving through cooperative grouping in Am. J. Phys. 60, p637-644. Mazur, E. (1996). The problem with problems in Optics and Photonics News 7, 59.     © Barbara Duch, Univ. of Delaware, 2001. Problem-Based Learning Clearinghouse