Problems. Problems! Everybody's got problems. Yet when faculty consider introducing problem-based learning into their courses, one of the perceived "problems" is a lack of suitable problems.
Adoption of the problem-based approach to learning can profoundly change one's notion of a good problem. End-of-the-chapter textbook problems suddenly seem inappropriate -- often contrived, narrowly focused, and vaguely irrelevant. A good problem typically involves a real situation, sequential components, and sufficient complexity to engage a group of students productively for up to a week or more. Case studies in business and medicine have these qualities. They require students to gain understanding, apply multiple concepts, and make decisions based on their work. Outside of business and medicine, where does an instructor find problems to use?
Unfortunately, published collections of problems do not exist for many subjects. Consequently, instructors usually write their own problems and case studies if they want to use problem-based instruction. While creating problems obviously takes time and may deter some instructors from adopting problem-based instruction, once started, the activity can be enormously stimulating. It becomes an intellectual challenge to write problems that pique students' curiosity, require analysis, and generally encourage learning. How students learn becomes as important as what they learn. One must reconsider what students really need to learn and the environment in which they learn. Much of the enthusiasm for the problem-based approach to learning comes from instructors who feel revitalized by the creative energy it releases.
Upon reflection, most instructors have little trouble identifying suitable topics on which to base problems. Problems can come from classic works that define the intellectual growth of a discipline. They can come from present and past controversies, clever application of important concepts to every-day situations, current events, or personal experience. The sources are almost unlimited. I rely heavily on the research literature in my disciplines as a source of problems. My approach was strongly influenced by a little book, "A Strategy for Education," written by Herman Epstein and published by Oxford University Press in 1970.
In the sciences, undergraduates rarely have to read the periodical scientific literature. Rather, they read colorfully illustrated, encyclopedic textbooks which are wonderful resources but reveal little about the development of current concepts and the process of science as a human activity. Epstein, sensitive to these issues and dissatisfied with teaching a watered-down biology major's course to non-science majors, taught introductory biology at Brandeis University without a textbook. Instead, he selected a chronological series of related research articles for his students to read. This "graduate seminar for freshmen" focused on the scientist, rather than the science. The articles were important documents revealing the scientists who wrote them, and the students learned a lot of biology. They also learned that science was more than a collection of facts; it was a rational way of finding out about the world that anyone could use.
One might think that science majors would appreciate the process of science and the motivation of scientists already but, in my experience, that is not the case. Consequently, in 1988 when the undergraduate biochemistry major was established, CHEM 342 Introduction to Biochemistry was among the required courses in the sophomore year. That course was based on Epstein's model but has continued to evolve with the increasing number of biochemistry majors. Without changing the content, CHEM 342 was transformed into a problem-based course two years ago. The articles became the problems and the lecture-discussion format was replaced by groups of four or five students working on the "problems" during class time. The biochemistry majors learn about the disciplines by reading, discussing, and ultimately understanding publications by research biochemists.
Although almost any biochemical theme could be used in a course like CHEM 342, I use a series of about ten articles which trace the history of our understanding of hemoglobin and its involvement in sickle cell anemia over the past century. The selections include classic articles by prominent scientists about discoveries whose significance extends well beyond the theme of the course. A one to two page, referenced introduction, and an overview accompanies each article. It provides information about the authors, sets the context in which the work was done, and connects the article with others used in the course. In addition to an introductory overview, each article comes with a succession of assignments culminating with one through which students can demonstrate their understanding of the article.
Invariably students do not understand an article when they first read it. Initially they must define learning issues -- words, concepts, procedures, etc., that they will need to learn about before they can understand the article. Defining one's ignorance is a most important first step in problem-based learning. During the first day of group discussion, students share their learning issues and attempt to resolve them. Those that remain at the end of class become group learning issues that are ranked in order of their perceived importance and assigned to group members to look up before the next class. After several iterations of this process, students demonstrate their understanding by completing a specific assignment such as: Write a 200-word abstract of the article. Conceptualize the article's conclusions with a diagram and legend suitable for a textbook or make up a problem for an introductory chemistry course based on the article. At other times they are asked to decide whether a researcher displayed racial prejudice in an article or whether a particular human experiment was ethically justified. Midterm and final examinations include individual and group parts modeled on the above activities.
A major individual assignment (problem) in CHEM 342 asks each student to select and study the lives and accomplishments of two prominent biochemists, identify some nontrivial theme that relates to both, and develop the theme in a term paper using the biographies. Students are encouraged with extra credit to interview their subjects after they have familiarized themselves with several significant articles by the biochemists.
Having taught CHEM 342 twice in a problem-based format, I have become even more aware of how rich the research literature is as a source of problems and how effectively the problem-based approach matches my idealized concept of the roles of students and teachers. As a result, I read the research literature with a notebook at my side where I can write rough drafts of problems for all the courses I teach. Next year my students in another course will learn about the chemical properties of DNA in a literature-based problem I call "Jurassic Park Revisited."