Session 6: Problem-Based Learning
Mort Sternheim announces the winner of this week's badge contest. She is Sheila Zabko. Mort asks participants if they are interested in a STEMTEC t-shirt. The vote is no.
Our session leaders, Deborah Allen and Hal White from the University of Delaware, are introduced. They will lead the morning's discussion of problem-based learning.
According to Allen and White, problem-based learning (PBL) suits the characteristics bachelor degree students say they need in industry, government labs, graduate programs, and as high school teachers. These characteristics are: problem-solving, integrating skills, and management skills.
The common features of PBL are:
These features meet the characteristics of a good course identified recently by the National Academy of Sciences (From Analysis to Action: Undergraduate Education in SMET, 1996). According to the NAS report, good courses are problem-driven, emphasize critical thinking, provide hands-on experience, and are taught in the context of topics students confront in their lives.
- Learning is initiated by a problem.
- Problems are based on real-life, open-ended situations.
- The information needed to solve the problems is not initially given. Students
- identify, find and use appropriate resources.
- Students work in permanent groups.
- Learning is active, integrated, cumulative, and connected.
The process used in PBL works something like the following: Students are presented with a problem and, working in groups, initially attempt to organize their ideas and determine their collective previous knowledge related to the problem. During this first discussion, students are also required to identify what they don't know but need to know to "solve" the problem (called "learning issues"). Students rank the importance of the learning issues and decide which should be followed up by the whole group and which can be assigned to individual students (who will later teach the rest of the group). In conjunction with the instructor, the students should also determine what resources are required to research the learning issues and where to go for the resources. When students reconvene, they integrate their new knowledge into the discussion but continue to identify new learning issues that require another cycle of definition, research, and integration.
Allen and White point out that PBL is a form of cooperative learning that depends for its efficacy on collaborative work. They then offer a number of suggestions for using small groups in PBL:
Hal White then forms groups of approximately four members each and distributes a problem for the groups to discuss. (See Attachment C for a copy of the problem, "Tom and the Dairy Farm," developed by Marcia Watson-Whitmyre.) Groups are given approximately 20 minutes to work on the problem.
- Set the stage early. PBL should be introduced early on in the course, not as a more advanced stage in learning.
- Use permanent groups of about four. Too many voices get lost in the roar; too few members and there aren't enough hands or minds. If groups change too often, the community that is essential to cooperative learning can't develop.
- Heterogeneously select the groups by ability, sex, etc.
- Rotate roles of responsibility with each group. The four necessary roles are: discussion leader (keeps group on track and maintains full participation); recorder (records assignments, strategies, unresolved issues, and data, and convenes the group outside of class); reporter (reports group ideas and process during discussions by the entire class and writes up the final draft of assignments); and accuracy coach (acts as designated skeptic by checking the group's understanding and finding resources). It's important that roles rotate so that different skills are practiced by each group member and the work load is fairly distributed.
- Have groups select their own ground rules and establish consequences for not following the rules. This gives members practice in both leadership and developing consensus, and invests them in group process. Having the group identify sanctions when members don't do their part is very important.
- Enact peer evaluation. Basic considerations here involve using predetermined written criteria that focus primarily on behaviors, performing at least twice during the semester, incorporating peer reviews into individual student grades, keeping the process simple, and making results known periodically.
White calls the group back to a full-room discussion and asks for responses to the problem. After a range of responses, Allen and White discuss a number of issues related to PBL process.
They note that it is possible to combine PBL with mini-lectures, but it's generally best to offer such lectures after students have had some initial time to ponder the "real world" problem-to put lecture material in context. In large and/or introductory classes, though, using the "book ends" approach already discussed, coupled with peer tutors, can avoid the kind of chaos to which such classes are sometimes prone.
But lectures aren't always necessary or useful-sometimes just sending students off to work on the problem is the best pedagogical strategy. Students should be encouraged to do follow-up research to the problem. This develops research as well as critical thinking skills.
They also suggest that instructors recognize the difference between practical solutions to a problem and the scientific or underlying principles the problem addresses. The goal in a science course is inevitably knowledge of the latter.
White acknowledges that PBL can be uncomfortable for students and faculty alike who feel that it is the instructor's job to instruct. But White argues that our real goal in the science classroom is to uncover material rather than cover it. He uses the analogy of cream vs. swiss cheese. A lecture is a lot like cream cheese-it's easy to spread but goes on very thinly and is pretty tasteless. PBL is a lot like swiss cheese-it has lots of holes, for certain, but ultimately it's a lot more satisfying.
White also addresses the issue of tutors. He assigns tutors to each PBL group in his own courses, although Allen does not. He feels that it's useful, especially early on, to ask students who have been through the class to work with groups. They serve as useful resources and can be a lifesaver in very large courses. But there are drawbacks-sometimes tutors can be too effective and relieve groups from some of the hard work that's necessary to real learning.
At 10:45, participants break.
At 11:00, they reconvene. Allen and White note that while before break they focused primarily on PBL process and the characteristics of good groups, they now want to turn to the characteristics of good PBL problems. They ask participants to rejoin their groups and talk about what they feel are such characteristics. The following list was generated.
Characteristics of Good PBL Problems:
Allen and White introduce Bloom's Cognitive Levels. They are:
- start with the familiar (must connect to students' lives and engage interest)
- meet the objectives of the course
- require group work
- offer a "hook" that provides interest
- adequately defined but open-ended for creativity
- clear expectations
- attainable solutions
- elicit multiple approaches
- challenging to instructor as well as students
- must evoke both or all sides of an issue
- doable in the time frame available to class
- phased or sequenced
- connected to prior knowledge but offer opportunities for new insights
- avoid sex and/or ethnic biases
They then ask groups to consider three different problems in light of Bloom's levels: What level of cognition does each of the problems reach?
- Evaluation-appraise, evaluate
- Synthesis-design, construct
- Analysis-differentiate, distinguish
- Application-apply, solve
- Comprehension-explain, interpret
- Knowledge-define, list, state
After discussion of each of the three problems, Allen and White note that most problems don't go beyond the comprehension level, but that good PBL problems extend all the way to evaluation.
Before closing the session on PBL, Allen and White offer two sources of information on PBL: the University of Delaware's PBL home page (which includes course descriptions and syllabi, sample problems, and About Teaching articles on PBL) at http://www.udel.edu/pbl/ and Kipp Herreid's (SUNY-Buffalo) case studies in science home page (which includes sample cases and an extensive bibliography of PBL and case study teaching) at http://ublib.buffalo.edu/libraries/projects/cases/case.html .
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