17 January 2012

Problem based learning in medical education

This article was first published on 3 March 2005.

Problem based learning in medical education


Problem-based learning (PBL) is probably the largest area of educational research in medicine today. PBL is based firmly as a constructivist implementation whereby learning occurs through interaction with the environment and particularly other people. This essay considers the impact of PBL upon medical education with a short consideration of how PBL may be used in training novice users to handle computers.

In its broadest sense, PBL is implemented by presenting students with problems which they have to solve. It may be useful to draw a distinction between liberal implementations of PBL, and strict. The strict implementations require a firmly constructivist outlook: tutors should not “teach” per se, but rather be an interactive guide to the learning process. The whole idea of constructivism is that the learner is responsible for their own learning: the tutor simply ensures that an effective framework is set up.

Liberal implementations of PBL however simply rely upon the presentation of problems to encourage learning. These do not necessarily require an interaction between the learners and the instructors, and may be taught in an orthodox manner (using a problem as a worked example, for instance).

Most research considers the strict view to be the correct implementation, though there is no unanimity amongst researchers.

Norman and Schmidt (1992)

Norman and Schmidt (1992) reviewed the psychological basis of PBL, and said that Barrows (1986) held that PBL fosters clinical reasoning due to its closer approximation with clinical practice. The rationale behind PBL was that the acquisition of knowledge depends upon several mechanisms: the activation of prior knowledge, elaboration, and that matching content improves the recall of information. In a review of the literature, Norman and Schmidt found that PBL did not improve general problem solving ability. Gaps in knowledge were also more apparent, though it is not clear whether this was due to the way in which the learners were tested (wouldn’t testing learners’ knowledge with an orthodox method necessarily be higher if they were if taught using an orthodox method). However, the authors found that knowledge tended to be retained for longer, even though the amount of knowledge was less. PBL also enhanced interest in the topic matter as well as self-directed learning skills.

Albanese and Mitchell (1993)

Albanese and Mitchell (1993) performed a large scale meta-analysis of research papers on PBL from 1972 to 1992. Comparison between the papers was difficult due to the different methods involved, but some interesting findings were noted.

Broadly, the authors concluded that PBL was seen as more “nuturing” and “enjoyable” by the students when compared to traditional expository learning. In clinical exams and faculty interventions, graduates performed as well, if not better, than those taught with conventional methods.

However, they noted that the central difficulty with their study was defining exactly what PBL was: Barrows (1986) had defined a taxonomy of PBL types, saying PBL was characterised as the “use of patient problems as a context for students to acquire knowledge about the basic and clinical sciences.” The method involved encountering the problem, applying problem-solving with clinical reasoning skills, identifying learning needs in an interactive (often collaborative) process, self-study, applying newly gained knowledge to the problem, and then summarising it. In shorter terms, PBL may be defined as iteratively and interactively learning information needed to solve a problem. Within PBL, students are given a greater responsibility for the direction of their learning, though the exact amount differs across curricula. The main instructional method is through the use of small group tutorials, and independent study.

The theory behind PBL (from Schmidt, 1983) has three main points of action. Firstly prior knowledge should be activated. Though prior knowledge should not be at all sufficient to solve the problem, there should be enough to begin to make an approach. The instructional method must activate this knowledge.

Secondly, there should be encoding specificity. There should be a similar context between the instructional problem and commonly encountered cases.

Thirdly, there should be elaboration of knowledge through interactions such as peer-review, explanation, and interaction with others (learners and tutors).

Critics of conventional learning hold that the context of the learning differs from the context in which the learning is applied, so much so that a reduction in effectiveness is probable. Coles (1990) postulated that PBL equates more closely to contextual learning theory.

Albanese and Mitchell investigated five questions of interest to their study.

  1. The expense of PBL. Was any additional cost of PBL was worth changing curricula for?
  2. Effectiveness of self-directed learning. Do PBL learners learn as well as conventional students?
  3. Clinical skills may not depend upon the breadth of knowledge but rather on some other skill, so does PBL inhibit clinical skill?
  4. PBL may only prepare students for interactive small-group learning: real life situations may require more, so how do PBL learners adapt to other work environments?
  5. What time demands are placed upon staff?

The difficulties in measuring the outcomes of PBL were manifold. No “gold standard” for PBL assessment existed, so a range of other assessments had to be used to infer learning success or failure (such as standardised clinical achievement tests, clinical ratings of graduates in residency, self-ratings of background preparation, whether first choices of residency were achieved and so on).

An additional problem for investigating PBL was the selection for the groups: students who were placed into PBL groups were self-selected. When a conventional track was studied along with a PBL track, both tracks tended to blend, at least socially if not academically. Even without these issues, extraneous variables were not adequately controlled. However, the authors contend that the weight of consistent evidence should at the very least provide some support for their conclusions.

In terms of basic science knowledge, PBL students fared less well than conventional students. This appeared to be a general finding, though not wholly consistent as it depended upon the implementation of PBL. The more directive a PBL course was, the less likely was the difference.

For clinical examinations, there were few consistent differences. For one study, the PBL students appeared to be more homogenised, whereas the conventional students were dichotomously distributed. The general trend was in favour of PBL, though this was not conclusive.

Thought processes showed an advantage for PBL for atypical cases, whereas the reverse was true for classic cases. Errors were greater and decisiveness was lower for PBL. There was evidence that PBL may interfere with forward (expert) reasoning of clinical cases for PBL students tended to employ backward reasoning.

PBL students seemed to have more valued study behaviours: conventional students placed an emphasis upon using lecture notes and reproductive methods, whereas PBL students valued versatile methods. Use of libraries, textbooks, journals and article increased for PBL students.

Conventional students reported being more stressed than PBL students at the start of term. This difference lessened towards the end of the year, but was still significant. This was not a unanimous finding as one study reported greater stress for PBL students. However, this may be due to the specific implementation rather than the technique of PBL in general. PBL students’ least satisfactory aspects of their courses were the competition and essay examinations. Their most satisfactory aspects were problem solving, group discussions, applicability, and clinical relevance. Conventional students least liked the reliance on fact recall and multiple choice questionnaires. They preferred individual excellence and group competence. One study showed that PBL students viewed their preclinical years as engaging, difficult, and useful. Conventional students in this study viewed their preclinical years as irrelevant, passive, and boring.

For achieving the first choice of residency, PBL students compared well with conventional students.

Schmidt et al (1996)

Schmidt et al (1996) investigated medical courses held in three different institutions. One used conventional instruction, the second used problem-based learning, and the third had an integrative approach (whereby biomedical and clinical sciences were integrated around the major organ systems). The latter approach had structured elements (such as prescribed books), patient demonstrations and small group training sessions.

The theory behind PBL courses was that exposure to real life problems will enhance the problem-based craft because it fosters clinical reasoning and problem solving skills, though Norman and Schmidt (1992) did not find evidence for this.

This study could be criticised, for each instructional method took place at a different institution: effects of the quality of tutors and students could have confounded the research questions asked, and it does not appear as though these factors were adequately controlled. However, an interaction between instruction method and year of study was found, as well as main effects of both instruction method and year of study. The latter finding indicated some validity to the study: one would expect students to score more highly as they progressed through the course.

Further analysis of the main effect of instruction method showed that the PBL and integrative curricular did not differ between each other, whereas the conventional curricular achieved marks significantly lower than them both. The interaction effect showed that the integrative method achieved significantly higher marks than the PBL and conventional curricular for years 2 and 3. years 5 and 6 reverted to mirror the main effect by showing the PBL and conventional methods achieving higher marks than the conventional method, but not differing between each other.

The authors considered this to show that the benefits of PBL only become apparent during the clinical years of a students learning (and “incubation” period). During the clinical training however, the benefits become markedly apparent as performance rises to the level achieved by the integrative curricular. An alternative explanation is that the clerkship of the institution with the integrative method was better than the other two, but this was considered unlikely.

Human-computer interaction and user instruction

There is no reason why the benefits of PBL could not transfer to the area of user training: indeed, given that good interfaces are designed to allow exploration, it may be that a short series of problem-based exercises is the best way for users to be trained.

The one outstanding issue on this matter is whether experience using PBL as a user training technique will foster a more effective level of problem solving on computers.

One of the more intimidating aspects of seeking help for novice users is the ‘RTFM’ (”read the f***ing manual“!) and various other insults heaped upon the shoulders of those who dare to ask a question that the expert considers obvious. These experts justify their response by saying that the answers to simple questions may be found with a little searching on the part of the novice.

Though I have not looked at the literature for PBL within user training, I am not aware of any good studies that have been done. It may be that teaching users to search for solutions themselves would be a better solution than teaching them parrot-fashion where to click for a specific task. Indeed, given the amount of money spent on helpdesk operations, instituting a policy of PBL instead of conventional instruction may help to reduce the costs that organisations incur when dealing with emplyee’s IT problems.

Conclusion

Problem-based learning appears to offer very real benefits to learning. While all the above studies focused upon medical education, it is entirely likely that the benefits of PBL will transfer to other domains that have a practical aspect to them (such as architecture, psychology, and even human-computer interaction.

References

Albanese M, & Mitchell S (1993). Problem-based learning: A review of the literature on its outcomes and implementation issues. Academic Medicine. 68(1), 52-81.

Barrows H.S. & Tamblyn R.M. (1980) Problem-Based Learning: An Approach to Medical Education. New York: Springer Publishing Company, p.1.

Norman GR, Schmidt HG. The psychological basis of problem-based learning: A review of the evidence. Academic Medicine. 1992; 67: 557-565.

Schmidt, G., Machiels-Bongaerts, M., Hermans, H., Cate, Th.J. ten, Venekamp, R., & Boshuizen, H.P.A. (1996). The development of diagnostic competence: comparison of a problem-based, an integrated and a conventional medical curriculum. Academic Medicine. 71(6): 658-664.
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