Problem*based learning in American medical education:an overviewBy Robert S. Donner, M.D.Professor and Chair, Department of PathologyHarmon Bickley, D.D.S., Ph.D.Professor, Department of PathologyMercer University School of MedicineMacon, Georgia 31207

The recent trend toward problem-based learning (PBL) in Americanmedical education amounts to one of the most significant changessince the Flexner report motivated global university affiliation. InPBL, fundamental knowledge is mastered by the solving of problems,so basic information is learned in the same context in which it willbe used. Also, the PBL curriculum employs student initiative as adriving force and supports a system of student-faculty interaction inwhich the student assumes primary responsibility for the process.The first PBL medical curriculum in North America was established atMcMaster University in Toronto in 1969. The University of NewMexico was the first to adopt a medical PBL curriculum in the UnitedStates, and Mercer University School of Medicine in Georgia was thefirst U.S. medical school to employ PBL as its only curricular offering.Many interpretations of the basic PBL plan are in use in NorthAmerican medical schools. Common features include small-groupdiscussions of biomedical problems, a faculty role as facilitator, andthe student's relative independence from scheduled lectures. Theadvantages of PBL are perceived as far outweighing its disadvantages,and the authors conclude that eventually it will see wider use at alllevels of education.

The recent trend toward problem-based learning (PBL)amounts to one of the most significant changes inAmerican medical education since the Flexner reportinstigated global university affiliation. Interest inmedical PBL has been driven by three major factors:a need to accommodate the growing volume ofknowledge required to practice medicine, the Generaland Professional Education of the Physician (GPEP)report [1] and, perhaps most important, the imple-mentation of a successful PBL curriculum at McMas-ter University [2]. Many schools now are investigat-ing the PBL concept, and some will adopt it withinthe next decade. It is important, therefore, that med-ical educators understand the basic structure of PBLand appreciate its advantages and limitations.

WHAT IS PBL?

PBL is a form of education in which information ismastered in the same context in which it will be used.Also, in its most recent medical forms, PBL is seen as

a student-driven process in which the student setsthe pace and the role of the teacher becomes one ofguide, facilitator, and resource.Contemporary PBL medical programs usually em-

ploy two fundamental principles: basic sciences arelearned in the process of analyzing typical cases, andlearning is motivated by student curiosity. These twoelements are manifest in many different ways. Forexample, in analyzing a case, the student always comesto a point where more information is needed to con-tinue. This results in the generation of an "issue." Anissue specifies an item of information that must belearned to complete the case. It always is stated inthe form of a question, such as "What are opsoninsand how do they work?" Once an issue has beenidentified, it becomes a learning goal for the nextmeeting. Each student then must find an answer tothis question and be prepared to share it with otherstudents. Thus, PBL employs student initiative as adriving force. The student generates the issues, pro-vides the answers, and teaches fellow students.

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The use of teaching cases in a conventional course,as practiced by many schools, appears similar to PBL,but the role of the student is far more passive. Inauthentic PBL, the student is asking the questions aswell as answering them, teaching as well as learning,assuming primary responsibility for the process. Ac-cording to a recent issue of JAMA devoted to medicaleducation, 100 medical schools had reported the useof PBL [3]. On closer inspection, however, it becomesapparent that most of this activity is case-enhancedteaching. While this is an effective learning mode, itis not a true PBL exercise, in that student initiativeis not the impetus.

GOALS OF THE PBL CURRICULUM

As used in medical education, the PBL curriculum isintended to meet three goals: the student must ac-quire a body of basic biomedical knowledge equiv-alent to that learned in a traditional curriculum, thestudent must learn to apply this basic knowledge inpatient care, and the student must acquire the atti-tudes, habits, and techniques of a lifelong learner.The first goal is identical to the central goal of a

conventional curriculum. Any successful medicalcurriculum must transmit an adequate store of bio-medical facts, or it will not survive the usual gauntletof extramural evaluation. In the PBL curriculum,however, provisions are made to meet the second andthird goals as well. Through the process itself, thestudent gains the ability not only to recite biomedicalinformation but also to use it in solving problems.Indeed, the very means by which learning is accom-plished is the solving of biomedical problems. Re-garding the third goal, the student's constant use oftextbooks, literature references, consultations, andother media impart the habit of learning and profes-sional interaction. In fact, it is the authors' impressionthat the PBL student comes to depend on texts andother library material far more completely than dostudents in a traditional program. PBL students areconditioned to correct any lack of information im-mediately as a case develops. They are not just advisedto be lifelong learners; they are trained to be.

HISTORY OF PBL IN NORTH AMERICA

The present burst of interest in the problem-basedmedical curriculum began at McMaster University in1969 [4]. In the McMaster setting, PBL was adoptedas part of a comprehensive reorganization, which alsoincluded the selection of students with nontradition-al educational backgrounds and complete integrationof basic biomedical sciences into a single program.McMaster's example was soon followed by otherNorth American medical schools. In 1979, The Uni-versity of New Mexico (UNM) became the first med-

ical school in the United States to offer a PBL curric-ulum. Its approach was to institute PBL as analternative track and to maintain a concurrent con-ventional curriculum as the standard instructionalformat. Most UNM students learn through a tradi-tional, lecture-based curriculum, while a small num-ber pursue PBL [5].

It was not until 1982, when Mercer University es-tablished its School of Medicine (MUSM), that a U.S.undergraduate medical institution began operatingwith full commitment to PBL. The MUSM opened itsdoors as a PBL school with complete basic scienceintegration and never has offered a conventional cur-riculum. Another milestone in the history of PBL wasits adoption by Harvard University School of Medi-cine, first as an alternative track and later as standardfor all medical students [6].Harvard and Bowman Gray medical schools are no-

table in the history of PBL because they representestablished schools that have converted to PBL froma traditional medical curriculum. Although such atransformation is expensive and politically difficult,in both cases the project seems to have been success-ful.While many medical schools around the world use

PBL, to the author's knowledge only four NorthAmerican schools currently offer only a problem-basedcurriculum with no conventional curriculum as a sup-plement or alternate. These four are McMaster, Mer-cer, Harvard, and Hawaii. Several medical schoolsoffer some version of a dual-track system in which asmall part of the class uses PBL. Some schools offer asingle curriculum that blends both concepts, that is,an integral PBL "stream" that parallels and reinforcesa traditional curriculum. Other schools employ aproblem-based course, a PBL elective, or even a PBLthird year. In all, many interpretations of the PBLcurriculum exist, none of which are absolutely "pure."In fact, many educators believe that a PBL curriculumis strengthened by a limited number of well-chosenlectures.

PBL AT MERCER UNIVERSITY

Since it opened in 1982, MUSM has been committed toan integrated, problem-based, community-orientedpreclinical curriculum. This curriculum is centeredaround the education of the family practice physician.In fact, the training of family practitioners always hasbeen MUSM's declared intention. The entire basicscience program is administered by only two de-partments, the Department of Basic Science and theDepartment of Pathology. Except for pathology, thereare no discipline-based administrative units involvedin basic science education.The basic science component of the preclinical cur-

riculum is integrated fully. No discipline-oriented

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courses are offered, no discipline-related examina-tions are given, and virtually no discipline-centeredlectures are scheduled. The two sponsoring depart-ments work together very closely to manage an in-structional program that is almost completely devoidof the usual divisions of information [7].As in other PBL programs, the MUSM lecture

schedule is replaced by a series of tutorial sessions.During each session, a group of six students meetswith one faculty member to discuss actual case prob-lems. Case study and analysis compose the very foun-dation of basic science education. It is important torecognize that all basic science information is learnedby participation in this case analysis program. Thereis no other track. At MUSM, three 3-hour tutorialmeetings are held each week. Attendance and par-ticipation are mandatory.As they pursue the basic science program, MUSM

students are taught clinical skills and community sci-ence. In these programs, students interact with sim-ulated patients and spend a number of afternoons inpreceptorship training with local primary-care prac-titioners. Somewhat surprisingly, the basic and clin-ical components have proven to be complementary.Because the Biomedical Problems Program is con-ducted through small-group meetings, the students'practical experiences actually are discussed duringbasic science training. (This is a wonderfully syner-gistic feature, not anticipated in the original designof the curriculum). In this way, real-life clinical prac-tice in a rural community becomes a laboratory ex-ercise for the illustration of basic science theory. Also,and even more unprecedented, basic science becomesapplicable to the care of patients. This would be nextto impossible in a conventional, lecture-based curric-ulum.

THE PBL CURRICULUM

The PBL curriculum, as used in medical education,usually involves at least five features, which are de-scribed in the following summaries.

The biomedical problemThe biomedical problem is a typical case of a diseasechosen to illustrate the area of basic science to bestudied. Analysis of this case results in the generationof issues, always in the form of questions. Answeringthese questions provides the facts needed to build thestudent's fund of knowledge.At MUSM, approximately 150 cases are studied in

the two-year preclinical curriculum. Of these, 137 areused for teaching and 13 for oral examinations. Casesmay be real or fictional and are selected to provokeissues appropriate for each major subject. For exam-ple, a case of lung cancer is used in the twelfth week,

during a curriculum phase dealing with disorders ofgrowth. In studying this case, students learn the basicconcepts of cancer, including genetics, carcinogene-sis, classification and nomenclature, why people diefrom cancer, and as much other information as canbe absorbed in the time available.

The small-group tutorial session

Small-group tutorial meetings serve as the center oflearning in the PBL curriculum. A group typicallyconsists of six to seven students and one or two facultymembers. Generally, everyone sits around one tableas equals. A blackboard and large paper tablets areavailable for developing issues. The faculty overseeris expected neither to be the source of all informationnor even to have information about every area beingdiscussed. His or her function is to serve as an in-formed facilitator who keeps student participationbalanced and knows enough to prevent gross mis-takes and avoid too much digression.

In the MUSM version, tutorial meetings occur onMonday, Wednesday, and Friday mornings, from 9:00A.M. to noon. The curriculum is divided into thirteenphases, each of which lasts for six weeks. A groupand its tutors meet for one phase, after which newgroups with new tutors are formed.

Student-directed learningIssues are generated by students. The faculty facili-tator assigned to each group does not take the leador specify what the students are to know. In the give-and-take of a small-group session, everyone serves aslearner and teacher. Once all issues are generated, thestudents arrange them into a priority sequence thatbecomes the agenda for the next meeting. At the nextsession, students share their answers to outstandingissues and identify another list to be covered at thefollowing session. In this way, the students determinewhat they will learn (within limits), how they willlearn, and how they will participate in the instruc-tional process. A set of learning objectives is providedfor each phase, but it usually is employed as a check-list in preparing for the examination.

Dependence on tutorial learningPerhaps the most salient characteristic of PBL is thecentral importance of the small-group meetings. Thesequence of subjects considered at these meetings setsthe schedule. Although lectures are not regarded asa primary mode of instruction, they are used to someextent by most PBL schools. At MUSM, for example,students may listen to one or two basic science lec-tures a week, but attendance is not mandatory.

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Reciprocal student-faculty evaluationThe typical PBL program usually contains provisionsfor both student and faculty evaluation. At MUSM,students are evaluated by both intramural and extra-mural means. A 200-item, multidisciplinary, objectiveexamination and a forty-minute case-analysis oral ex-amination are given at the end of each of the thirteencurricular phases. In addition, each student must passstep 1 of the United States Medical Licensing Ex-amination series before being admitted to clinicaltraining. Faculty evaluation by students also is partof the end-of-phase ritual. Each student completes adetailed report on the tutor, including both standardforms and free form comment.

BENEFITS OF THE PBL CURRICULUM

Most faculty who have taught in both conventionaland PBL curricula favor the latter, largely because itseems a more natural format for learning and containsmany built-in motivational features. For example, noPBL student would make a practice of coming to tu-torial sessions unprepared. This may happen occa-sionally, but, if it becomes routine, other members ofthe group will complain loudly that the student isnot supplying an equitable amount of information.Students routinely prepare for each tutorial sessionwith five to eight hours of study. In contrast, moststudents in a lecture-based program do not study untilafter the class meeting is over.A second benefit of PBL is that students become

skilled at an eclectic style of learning. MUSM stu-dents employ texts, monographs, periodical litera-ture, and a wide variety of other sources. Overem-phasis on a lecture tends to discourage this. Often, ina traditional curriculum, many students may skip lec-tures altogether. Having failed to receive current,scheduled information firsthand, they will come todepend on notes and other handout material pre-pared by the professor. This is never the case in aPBL format, where many different resources must beconsulted. In fact, it is not uncommon for PBL stu-dents to come up with conflicting information andhave to reconcile the differences in group discussion.This leads to the realization that there may be morethan one answer to a question and serves to developa habit of critical thinking.Owing to longer hours of closer student-faculty

contact, the PBL curriculum is perceived by the stu-dent as more egalitarian than the conventional cur-riculum and seems to promote better student-facultyrelationships. Also, although evidence is largely an-ecdotal at this time, many clinicians believe that PBLstudents adapt more readily to the clinical clerkshipthan do other students.

DRAWBACKS OF THE PBL CURRICULUM

Reported disadvantages of the PBL curriculum in-clude cost, high faculty workload, variable tutor qual-ity, and the need for supplemental training in grossmorphology. The cost disadvantage relates primarilyto faculty time expenditure. One study [8] reportedthat it takes between 500 and 600 hours of facultytime to provide 130 hours of lecture in a traditionalmedical school. This does not vary appreciablywhether student enrollment is 10 or 300. The cost perstudent is not fixed and actually decreases with great-er student numbers. In the PBL curriculum, however,the cost per student is more or less fixed and increasesin direct proportion to the size of the student pop-ulation. This is because one faculty member is re-quired for each group of six students. The two cur-ricular styles seem to incur approximately equal costwhen student populations number about fifty. Theyare not exactly comparable, however, because in aconventional curriculum, perhaps only about onethird of the students attend lectures. This raises theactual cost per student to a much higher level.

FUTURE OF THE PBL CURRICULUM

PBL creates a stimulating and supportive environ-ment in which to teach and learn. Its educationalefficacy is well established, and faculty who have usedit have become its most devoted supporters. The eco-nomic issues are authentic but are related to scale andare not insurmountable.The greatest barrier to PBL may be political. Adop-

tion of a PBL curriculum necessitates a radical changein faculty and administrative attitudes. Faculty mustbecome more exposed to students, departments mustrelinquish some curricular authority, curricular mat-ters must assume a more important status. Suchchanges are not easy to enact in an established, con-ventional school. The advantages of PBL are persua-sive, however, and the authors feel that the futurewill bring even greater use of PBL at all levels ofeducation.

REFERENCES

1. MULLER S. Physicians for the twenty-first century: reportof the project panel on the general and professional edu-cation of the physician and college preparation for medi-cine. J Med Educ 1984 Nov;59(II Part 2):1-208.2. NEUFELD VR, WOODWARD CA, McLEOD SM. The McMas-ter MD program: a case study of renewal in medical edu-cation. Acad Med 1989;64:423-32.3. JONAS HS, ETZEL SI, BARZANSKY B. Educational programsin US medical schools. JAMA 1991;266(7):913-20.4. NEUFELD, op. cit.5. KAUFmAN A, MENNIN S, WATERmAN R, DuBAN S ET AL.

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The New Mexico experiment: educational innovation andinstitutional change. Acad Med 1989;64:285-94.6. COLVIN RB, WETZEL MS. Pathology in the new pathwayof medical education at Harvard Medical School. Am J ClinPathol 1989;92 (suppl. 1):S22-S30.7. BICKLEY H, DONNER RS, WALKER AN, TiFr JP Er AL. Pa-thology education in a problem-based medical curriculum.Teach Learn Med 1990;2:38-41.

8. DONNER RS, BICKLEY H. Problem-based learning: an as-sessment of its feasibility and cost. Hum Path 1990;21(9):881-5.

Received December 1992; accepted January 1993

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