8
Gijbels, 2003; Gallagher, Stepien, & Rosenthal, 1992; Hmelo, Holton, &
Kolodner, 2000; Hmelo-Silver, 2004; Torp & Sage, 2002).
PBL is an instructional strategy. That is, it is an instructional solution designed to improve learning by requiring students to learn content while solving problems. As such, PBL is:
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problem-focused, where learners begin learning by addressing simulations of an authentic, ill-structured problem;•
student-centered, because faculty cannot dictate learning;•
self-directed, where students individually and collaboratively assume responsibility for generating learning issues and processes through self-assessment and peer assessment and access their own learning materials;•
self-reflective, where learners monitor their understanding and learn to adjust strategies for learning.The PBL process normally involves the following steps:
1. Students in groups of five to eight encounter and reason through the problem. They attempt to define and bound the problem and set learning goals by identifying what they know already, what hypotheses or conjectures they can think of, what they need to learn in order to better understand the dimensions of the problem, and what learning activities are required and who will perform them.
2. During self-directed study, individual students complete their learning assignments to understand the problem and its possible solutions. They collect and study resources and prepare reports to the group.
3. Students share their learning with the group and revisit the prob- lem, generating additional hypotheses and rejecting others based on their learning.
4. At the end of the leaning period (usually one week), students summarize and integrate their learning.
PBL was implemented in the medical-school curriculum at the University of Missouri in 1997. Replacing the basic sciences approach to learning medicine, students from their first day work in groups to solve diagnostic medical problems such as that displayed in Table 8.1.
Note that this case is somewhat structured with question prompts.
During later stages, those prompts are removed.
Throughout their two-year medical program, students learn anat- omy, physiology, biochemistry, immunology, etc., while diagnosing patient problems, such as that in Table 8.1. In the first four years of the 154 • Cases
Table 8.1
First year PBL medical case, with permission, Michael C. Hosokawa, author All in the Family
Session 1
Mrs. Samson comes to the clinic today because she has felt fatigued. About a month ago, she said that she began to notice that she was tired most of the time.
The doctor asks if there have been any stressful times during the last month that might be causing fatigue. She says her life has been pretty normal for a mother of two teenagers. She laughs.
You ask if she started an exercise program or if she has been working especially hard.
She says that she wishes she could start exercising, but she does walk at the mall three mornings each week with a friend.
You ask if she has been eating a balanced diet or if she has changed her diet. She says she probably eats a little too much, but she does get a balanced diet.
Why is the physician asking these questions?
Are there other questions you would ask Mrs. Samson?
Patient History
Mrs. Samson is a 36 y.o. patient who has had one previous visit for a sprained ankle.
She is married and has two children, a boy 15 and a girl 13. Both pregnancies were normal. Deliveries were vaginal without incident. Mrs. Samson works as the branch manager for a local bank. She has a bachelors degree in finance and a MBA. She has been married for 18 years. Her husband is a high school principal. Mrs. Samson is active in her church and volunteers at the senior citizens center once a week to help with the meals program.
What would you do next?
Physical Exam
Ht. 170 cm Wt. 67 kg P 73 BP 122/80 mmHg R 16 Temp 36.8 degrees C
HEENT: Tympanic membranes and external auditory canals clear bilaterally. Pupils equal, round and reactive to light and accommodation. Nasopharynx clear, no lesions, no erythema or exudate. Dentition normal. Neck supple, no thyromegaly, no lymphadenopathy.
Lungs: Clear to auscultation Heart: Regular rhythm Breasts: No masses
Abdomen: Nontender, bowel sounds normal, liver and spleen nonpalpable, no masses
Extremities: Pulses intact, no edema, no cyanosis, no joint abnormalities Neurologic: Reflexes symmetrical and 2+
Pelvic exam: Normal
Make a list of terms you do not understand. How would you find out what these terms mean?
What are your conclusions based on these physical exam results?
The doctor asks Mrs. Samson if she has had any other symptoms other than fatigue.
(Continued Overleaf) Cases as Problems to Solve • 155
Table 8.1 Continued All in the Family
Mrs. Samson pauses and looks at the floor. “Well, I have noticed streaks of blood when I have a bowel movement.” She seems embarrassed. “This has happened several times each week. I’ve been sort of worried about this because my brother who was 9 years older died of intestinal cancer last year and my father died of cancer of the large intestine when he was 50. I know there were other people in my family with cancer, but I don’t know what kind they had.”
The doctor tells Mrs. Samson that he wants her to go to the lab in a few minutes to draw blood for some tests and there is one more test I want you to have. “The nurse will give you a packet to take home. The test is called a homoccult test and it is to determine if there is blood in the stool. The nurse will explain how to do the test.”
Mrs. Samson seems confused. She says, “Well, I can see blood.” The doctor explains,
“you want to know if blood is there even if you cannot see it. I am going to schedule you for another appointment in about two weeks. I am also going to schedule you with another doctor for a colonoscopy. The nurse will set up the appointment, tell you how to get to the clinic and give you some instructions. With the colonoscope, the doctor can look at the inner part of your intestine and maybe find the cause of the bleeding.”
Lab Results
Heme Profile: Hct 35% MCV 86µ3 Hgb 12.2 gm/dL MCH 30µµ3 WBC 8400/mm3 MCHC 32%
WBC Diff: neuts 62%
lymphs 34%
monos 4%
platelets 1850,000/mm3 SMAC:
glucose 145 mg/dL cholesterol 225 mg/dL Na 140 mEq/L alkaline phos 95 U/L K 4.6 mEq/L total bilirubin 1.2 mg/dL Cl 104 mEq/L direct bilirubin .2 mg/dL BUN 17mg/dL AST 30 U/L
Creatinine 1.0mg/dL ALT 35 U/L Calcium 917mg/dL LDH 142 U/L Phosphate 3.8mgdL CK 76 mU/ml Protein 7.2 gm/dL
Albumin 4.1 gm/dL Uric Acid 5.3 mg/dL
What is your differential diagnosis. What is a differential diagnosis?
What is the structure of the digestive tract. How does it function?
What is a hemoccult test? What is a colonoscopy? What is a sigmoidoscopy?
156 • Cases
program, students learning through PBL achieved higher scores on the Medical Licensure Examination than students who completed their program under the traditional curriculum (Blake, Hosokawa, & Riley, 2000). That trend was continued in the following years as PBL students generally outscored traditional students on the exam (Hoffman, Hosokawa, Blake, Headrick, & Johnson, 2006). In addition to improved exam scores, graduates received improved evaluations from residency program directors and preferred selections for residencies. PBL at Missouri better prepares graduates with the knowledge and skills that are needed to practice within a complex healthcare system.
A great deal of research has generated mixed results for the effects of PBL. Although early studies showed few advantages and some dis- advantages for PBL, more contemporary research on PBL has shown that PBL students:
Research Break Session 2
Mrs. Samson returns to the clinic two weeks later. The doctor tells her that the hemoccult test was positive indicating that she had blood in the stool. She has been scheduled for her colonoscopy next week.
Dr. Radford performs the sigmoidoscopy. Following the procedure, the doctor meets Mrs. Samson in the conference room. He explains that he was able to see numerous polyps on the surface of the large intestine. He wants to do another test, but based on her family history and the tests he has done, he is pretty sure Mrs. Samson has a disease called familial polyposis coli.
Research Break Session 3
Using P as the symbol for the dominant gene for familial polyposis coli and p as the symbol for the recessive normal gene, the doctor explains to Mrs. Samson how this disease has affected her family. There is no evidence of colon cancer in her husband’s family.
What are the chances that Mrs. Samson’s two children will have familial polyposis coli?
What if this disease were transmitted by a recessive gene?
Using the following symbols, work out a pedigree of Mrs. Samson’s family.
Mrs. Samson’s father died of colon cancer. Her mother is living and healthy. Her brother died of colon cancer. Her younger sister, age 32, is healthy. Her brother has one teenage child, 17 years old. The brother is divorced and Mrs. Samson does not know much about her brother’s ex-wife. Her younger sister has two children. She has no other siblings. Her uncle (her father’s brother) is living and has high blood pressure and diabetes. Mrs.
Samson’s grandparents on her father’s side of the family both died of heart disease in their sixties. Mrs. Samson’s grandparents on her mother’s side of the family both died in an automobile accident in their fifties.
What is your treatment plan for Mrs. Samson?
Cases as Problems to Solve • 157
•
consistently retain knowledge, especially more principled know- ledge, for longer periods of time than students in a traditional curriculum;•
apply basic science knowledge and transfer problem-solving skills in real world professional or personal situations more effectively;•
become more self-regulated, lifelong learners.(Hung, Jonassen, & Liu, 2008) In a follow-up qualitative meta-synthesis of PBL research, Strobel and van Barnveld (2009) concluded that PBL resulted in superior long-term retention, skill development and satisfaction of students and teachers, while traditional approaches were more effective for short-term reten- tion as measured by standardized board exams.
The rationale for problem-based learning is provided by two impor- tant contemporary theories of learning: situated learning and cognitive apprenticeships.
WHAT IS SITUATED LEARNING?
Learning in informal contexts in the everyday world is an activity-based and socially mediated phenomenon that occurs naturally in commu- nities of practice (Lave & Wenger, 1991). Communities of practice are any naturally emergent group of people who work together to accom- plish some activity usually involving social collaboration between individuals with different roles and experience. Rather than defining learning in terms of exam performance, knowledge is assessed by the individual’s ability to participate in that community. Rather than learn- ing content devoid of context and meaning, learning in communities of practice is focused on becoming a fully participating member of that community. That is, meaningful learning requires active and pur- poseful participation in a community that requires immersion in the activities of the community. The persons who learn the most naturally move toward the center of that community of practice (Lave & Wenger, 1991). In work groups, for instance, the most learned person is the one whose knowledge about how to do something is accessed most often.
Learning in situ in communities of practice results from an interaction of learning processes, activity, and context.
When learning in situ, the knowledge that is constructed by learners is situated in the context in which it is learned. That does not mean that learning is always situated in authentic environments. Learning is always situated in some context or learning culture, even elementary, high-school or college classes (Brown & Duguid, 1994). So there exist 158 • Cases
everyday contexts (often called the real world) and classroom contexts (which also exist in the real world). Those in-school contexts and cultures define expectations for all types of intellectual and social per- formance. Whatever learning does occur is the product of the activity, context, and culture in which the learning occurs. Learners are required to negotiate meaning and to construct understanding in culture through collaborative social interactions (Brown, Collins, & Duguid, 1989).
Situated learning theory emerged from anthropological studies of informal learning (Lave & Wenger, 1991; Rogoff & Lave, 1984; Suchman, 1987). In an ethnographic study of refrigeration technicians in a supermarket chain, a former student of mine (Henning, 1998) found that learning in situ is mediated largely by conversations, primarily in the form of stories (see Chapter 12), that is, negotiation with each other and with the machines that these technicians were servicing and the tools they used to perform the services. Learning was also manifest in the social relationships among the technicians. Evidence of learning was manifest in their professional identities both within the community of practice and in the larger supermarket community.
WHAT ARE COGNITIVE APPRENTICESHIPS?
The oldest form of instruction is an apprenticeship, where a novice learns a trade by practicing the skills of the trade in the normal context of that trade using the normal tools of that trade. In formal education, however, students too often learn about professions but seldom learn how to transfer that learning to contexts in the everyday world.
Apprentices do not have to transfer to new situations because they have learned to perform them in situ. In cognitive apprenticeships (Brown et al., 1989; Collins, Brown, & Newman, 1989), students are enculturated into authentic practice by solving problems and performing activi- ties that simulate a real apprenticeship. Cognitive apprenticeships are pseudo-apprenticeships in which students learn to think and perform like masters. While serving cognitive apprenticeships, teachers and professors function as master, who:
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teach knowledge and skills in everyday and professional contexts;•
teach in multiple contexts and generalize across contexts;•
model processes and explain reasons for those processes;•
make information more explicit, helping learners develop know- ledge about when and where to apply information;•
coach students (provide hints, feedback, and support) while moni- toring students’ progress;Cases as Problems to Solve • 159
•
articulate students’ actions, decisions, strategies to make know- ledge more explicit;•
include reflection and analysis of students’ performance;•
enable students to test various strategies and hypothesis and experience their effects;•
sequence instruction from simple to complex, using a variety of examples in different contexts.Rather than learning to think like students, students serving cogni- tive apprenticeships learn to think like a master. Cognitive apprentice- ships make explicit the decision making required to perform like a master. Often conventional apprenticeships (or mentoring) deal only with algorithmic problem solving, and any real decision making is left implicit. That is one of the reasons why apprenticeships are so inefficient and highly variable in their effectiveness.
PSLEs are perhaps the most appropriate medium for engaging students in cognitive apprenticeships. Engaging students in solving authentic problems to solve and supporting their problem-solving per- formance with cases as analogues, prior experiences, and perspectives and scaffolding that performance with tools and strategies that support schema development, problem definition, information searching, ana- logical and causal reasoning, and argumentation provides a complete cognitive apprenticeship environment.
WHAT IS AN AUTHENTIC PROBLEM?
Situated learning theories stress the importance of embedding instruc- tion in authentic, everyday problems. As stated before, learning always occurs in some context. The assumption of this book is that by engaging students in solving more authentic problems, more authentic, socially mediated, and personally relevant kinds of learning will result.
However, there have emerged two broad conceptions of authenticity:
preauthentication and emergent authenticity. Preauthentication refers to analyzing activity systems and attempting to simulate an authentic problem in a learning environment. Preauthentication is what Barab and Duffy (2000) refer to as a practice field, in which students can practice learning how to function in some field, such as mathematics.
The other conception of authenticity is a field of practice (Barab &
Duffy, 2000) in which students are embedded in an authentic setting, allowing them to learn a skill by engaging in the activities germane to that field (Barab, Squire, & Dueber, 2000; Nicaise, Gibney, & Crane, 2000; Radinsky, Buillion, Lento, & Gomez, 2001). Fields of practice 160 • Cases
possess attributes of apprenticeships. The authenticity emerges from the practice in an authentic setting.
This book generally focuses on presenting preauthenticated prob- lems to students as a form of cognitive apprenticeship within the normal constraints of formal education. However, virtually all of the recommended uses of cases and cognitive skills apply equally well to both kinds of problems, regardless of whether the problem to solve is preauthenticated or emergent. Whichever kind, preauthenticated or emergent, the problem should be the focus of the learning.
WHAT MODELS OF PROBLEM-SOLVING LEARNING ENVIRONMENTS EXIST?
There have been several implementations of situated learning and cognitive apprenticeships. Two of the better-known implementations include anchored instruction and goal-based scenarios.
WHAT IS ANCHORED INSTRUCTION?
Perhaps the best known and most effective implementation of situated learning is anchored instruction. Based on situated-learning theory and cognitive apprenticeships, anchored instruction embeds problems into complex and realistic scenarios, called macrocontexts. Developed by the Cognition and Technology Group at Vanderbilt (1991, 1993), anchored instruction uses high-quality video scenarios for introducing a problem and engaging learners in order to make the problems more motivating and easier to search. The video is used to present a story narrative that requires the learners to articulate the problem to be solved, rather than having the entire problem circumscribed by the instruction. All of the data needed to solve the math and science prob- lems are embedded in the story, enabling students to make decisions about what data are important. The problems that students generate and solve are complex, often requiring more than twenty steps to solve, rather than simple story problems.
The Cognition and Technology Group at Vanderbilt designed and developed two full series of video-based problems: The Adventures of Jasper Woodbury and Scientists in Action. The Adventures of Jasper Woodbury consists of twelve video-based adventures (plus video-based analogs, extensions and teaching tips) that focus on mathematical problem finding and problem solving. Each adventure is designed from the perspective of the standards recommended by the National Council of Teachers of Mathematics. In particular, each adventure provides Cases as Problems to Solve • 161
multiple opportunities for problem solving, reasoning, communica- tion, and making connections to other areas such as science, social studies, literature, and history.
In the geometry series for grades 5 and up, Paige Littlefield, a Native American, is following a set of clues to find a family heirloom her grandfather left for her in a cave. As Paige searches for the cave we learn about topographic maps and concepts of geometry important for measurement. An accident occurs when Paige reaches the cave.
Students must help her friend, Ryan, find the cave on a map and give directions for the Rescue Squad to get there as quickly as possible.
Incorporating real-world map-reading skills with angle and linear measurement, this is a challenging episode for math and social studies.
In the series Working Smart, teenagers Jasper, Emily, and Larry com- pete in a problem-solving contest sponsored by a local travel agency.
They set about creating mathematical “smart tools” that will allow them to solve several classes of travel-related problems efficiently and quickly in hopes of winning an all-expenses-paid trip anywhere in the USA. All three episodes help students see the power of algebra, demonstrating that a mathematical representation can be created from a whole class of problems.
Using the same set of assumptions used to design the Jasper series, the Young Scientist series provides scientific adventures for students to solve. In the Stones River Mystery, students in the field and in an electronically connected classroom have been monitoring a local river for pollution. During one sampling trip they notice that the measures they are monitoring have begun to change. The students and scientists must work together to determine where the pollution in coming from.
In the Lost Letters of Lazlo Clark, a “time capsule” has been found during a renovation of the local high school. In it are letters and a map from Lazlo Clark, a local philanthropist who had donated a large tract of land to the area almost 100 years ago. Students and their science teacher set out to find some Native American petroglyphs mentioned in Clark’s letters. While their initial trip is not successful it helps them understand the importance of planning to make such a trip and how much science is needed.
Anchored instruction has proven very successful in both engaging students and getting them to solve problems more complex than their teachers thought possible. The basis of their success is student owner- ship of the problems.
The Jasper Series of video-based story problems, on the other hand, has been shown to successfully engage students in complex mathemat- ical problem solving and transfer (Cognition and Technology Group 162 • Cases