|Teaching and Learning Forum 2010 [ Refereed papers ]|
Nita Sodhi-Berry and Helena Iredell
School of Population Health
The University of Western Australia
Problem based learning (PBL) is a small group learning method widely used in medical education. However, educators have concerns with its potential for group dysfunction, the difficulty in truly accomplishing self-directed learning and its sustainability. Yet it is recognised that medical education wishes to retain small group teaching that is interactive and collaborative in nature but develop one that has efficacy in educational practice, attaining the learning outcomes and resource use. Case based learning (CBL) has been acknowledged as a more structured approach to collaborative learning that consolidates and integrates newly acquired knowledge and skills. Little research has compared PBL with other small group methods. This study investigated students' perceptions towards CBL and PBL, after a pilot CBL intervention in a core unit.
All Year 2 and Year 3 students enrolled in the medical degree at The University of Western Australia received the CBL intervention over six weeks in a core unit, after experiencing PBL for at least 1.5 years. Of all students, 82.3% (n=255) completed a 22-item questionnaire about their perceptions towards the relative advantages of these two methods. An overwhelming 79% (n=201) of students strongly supported CBL, with only 12% (n=30) supporting the PBL method. This tremendous support for CBL over PBL was consistent across both year 2 and year 3, as well as for both males and females, with no significant difference between the different groups (p>.05). The majority of students perceived case based learning as having more advantages than problem based learning, with CBL being able to achieve most of the recognised benefits of PBL. CBL is a promising alternative to PBL in medical education, offering a more sustainable alternative that still captures the positive characteristics of PBL but in a way that is more efficient in resource utilisation.
Analysis of clinical problems using interactive discussions, have been found to be more effective in enhancing problem relevant information processing and retention than analysis done at an individual level (Dolmans, De Grave, Wolfhagen, & Van der Vleuten, 2005; Schmidt & Moust, 1998). Of the various interactive group based teaching methods available, problem based learning (PBL) is the most heavily supported in academic medical literature. It is described to be more effective and popular than the traditional didactic methods of teaching (Albanese & Mitchell, 1993; Dolmans et al., 2005; Norman & Schmidt, 2000; Schmidt, 1983). There are various approaches to problem-based teaching methods in that they differ with respect to the degree of teacher- or student- centred approach, the format and sequence of the problems and the educational objectives specific for a topic (Barrows, 1986). This paper focuses on two different small-group teaching strategies in medical teaching and learning; problem based learning (PBL) and case based learning (CBL).
Essentially, PBL is described as a motivating process of free inquiry in which a small group of students collectively explore an ill-structured clinical problem (Barrows, 1986; Schmidt, 1983; Srinivasan, Wilkes, Stevenson, Nguyen, & Slavin, 2007). PBL students work together to identify their learning needs and proceed through exploration, discussions and evaluation to reach a consensual conclusion with minimal direction from the tutor (Barrows, 1986; Schmidt, 1983; Tarnvik, 2007). Likewise, CBL derives these main features from PBL of being a collaborative learning approach, but the students encounter the problem individually after being educated in the concepts, and it is also referred to as a teacher-directed inquiry approach (Albanese & Mitchell, 1993; Barrows, 1986; Srinivasan et al., 2007; Williams, 2005). While PBL students are expected to discover their mistakes themselves, CBL students have access to expert advice from the tutor who shares the responsibility of solving the problems (Katsikitis, Hay, Barrett, & Wade, 2002; Srinivasan et al., 2007). This is the primary difference between these two modes of small group teaching (Williams, 2005). While PBL stimulates discovery of basic knowledge to understand new concepts, CBL ensures the consolidation of newly acquired knowledge through its application and discussions (Tarnvik, 2007). Although PBL has been compared extensively to the traditional didactic ways of teaching (Albanese & Mitchell, 1993; Colliver, 2000; Dolmans et al., 2005; Norman & Schmidt, 2000; Schmidt, 1983), limited research has been done in comparing it with other modes of small group teaching, like case-based learning (CBL) (Katsikitis et al., 2002; McNaught, Lau, Lam, Hui, & Au, 2005; Srinivasan et al., 2007; Williams, 2005).
For the CBL intervention, the students were required to come prepared to the tutorial after attending the lecture and doing the pre-readings and researching the learning outcomes so as to enable active discussions and debates around the clinical problems. The second year students studied the musculoskeletal system, while the third year students covered the cardiovascular and gastrointestinal systems. A new case provided the focus of study within a system each week, with each cycle of CBL running for a week. The case was presented progressively in the session and the students with the tutor's guidance, engaged in the case to discuss and come up with solutions for dealing with the scenario and highlighting the issues particular to the health issue. The tutors were provided with literature and interactive training in both problem based and cased based learning prior to the commencement of the teaching semesters.
|Stated condition||% Students supporting CBL |
(Agree and Strongly agree)
|% Students supporting PBL|
(Agree and Strongly agree)
|Has advantages over the other method||76.7||80.7||77.5||78.0||78.8||17.5||6.7||15.7||9.2||11.8|
|Makes efficient use of time||77.5||85.2||74.5||85.8||81.6||14.2**||5.2||12.8||7.1||9.4|
|Structure and environment promotes learning||84.2||85.2||83.3||85.1||84.7||39.2||35.6||38.2||38.3||37.3|
|More opportunity to explore related topics||81.6||73.0||76.5||76.6||76.9||26.7||26.7||25.5||27.0||26.7|
|Less unfocussed discussions||50.8||63.0||64.7||51.8||57.3||22.5**||8.2||15.7||13.5||15.0|
|Opportunities to apply knowledge and skills to cases||78.3||77.0||77.5||77.3||77.7||20.8||15.6||24.5||14.2||18.0|
|Promotes discussion and participation||75.0||72.6||74.5||73.1||73.7||43.3||46.7||43.1||47.5||45.1|
|More opportunity for tutor participation and feedback||51.7||55.6||55.9||51.8||53.7||44.2||32.6||46.1||34.0||38.0|
|Helps development of clinical problem solving skills||65.0||65.2||67.7||63.1||65.1||38.3||37.8||39.2||36.2||38.0|
|Encourages skills for finding and using resources||63.3*||44.4||51.0||53.9||53.3||30.0||28.2||39.2||22.0||29.0|
|Encourages self-directed learning||68.3||65.2||66.7||66.7||66.7||35.8||38.5||40.2||34.8||37.3|
|** p<.01, * p<.05|
There are significant differences (p <.0001) within the second year, third year, male and female students' responses to the perceived benefits of CBL over PBL (Table 2). The overwhelming support for CBL over PBL is consistent across both the years of study as well as for both gender, with no significant difference between the opinion of second and third year, or between male and female students (p>.05) (Table 1). Furthermore, second year students and male students did not find any significant difference between PBL and CBL in terms of more opportunity for tutor participation and feedback (p >.05) (Table 2).
On comparing the difference in the mean responses to CBL and PBL between second year and third year students, both groups were found to favour CBL over PBL. While there was no statistically significant difference for most questions between the two levels of study, the third year students were found to support efficient use of time and unfocussed discussions in CBL more strongly than second year students (p<.01) (Table 2).
|Stated condition||YR 2 Mean (SD)||YR 3 Mean (SD)||MALE Mean (SD)||FEMALE Mean (SD)|
|Has advantages over the other method||3.9 (0.9)***||2.6 (0.9)||4.0 (0.6)***||2.4 (0.8)||3.9 (0.8)***||2.5 (1.0)||4.0 (0.7)***||2.4 (0.8)|
|Makes efficient use of time§||3.9 (0.8)***||2.6 (0.8)||4.0 (0.6)***||2.3 (0.8)||3.8 (0.8)***||2.5 (0.9)||4.0 (0.6)***||2.5 (0.7)|
|Structure and environment promotes learning||3.9 (0.6)***||3.2 (0.9)||4.0 (0.5)***||3.1 (0.9)||3.9 (0.6)***||3.2 (0.9)||3.9 (0.6)***||3.1 (0.8)|
|More opportunity to explore related topics||3.9 (0.6)***||2.9 (0.9)||3.8 (0.7)***||2.9 (0.9)||3.8 (0.7)***||2.9 (0.9)||3.8 (0.6)***||2.9 (0.9)|
|Less unfocussed discussions§||3.4 (0.9)***||2.8 (0.9)||3.6 (0.9)***||2.5 (0.9)||3.6 (0.9)***||2.5 (0.9)||3.5 (0.9)***||2.7 (0.9)|
|Opportunities to apply knowledge and skills to cases||3.9 (0.8)***||2.8 (0.9)||3.9 (0.6)***||2.7 (0.9)||3.9 (0.7)***||2.8 (0.9)||3.9 (0.7)***||2.7 (0.8)|
|Promotes discussion and participation||3.9 (0.7)***||3.2 (0.9)||3.8 (0.7)***||3.2 (1.0)||3.9 (0.8)***||3.2 (0.9)||3.8 (0.7)***||3.3 (0.9)|
|More opportunity for tutor participation and feedback||3.5 (0.8)||3.2 (0.9)||3.5 (0.8)**||3.2 (0.9)||3.5 (0.8)||3.3 (0.9)||3.5 (0.8)**||3.2 (0.8)|
|Helps development of clinical problem solving skills||3.8 (0.8)***||3.1 (0.9)||3.7 (0.7)***||3.1 (0.9)||3.8 (0.7)***||3.1 (1.0)||3.7 (0.8)***||3.2 (0.8)|
|Encourages skills for finding and using resources||3.7 (0.8)***||3.0 (0.9)||3.4 (0.8)***||3.0 (0.9)||3.5 (0.9)*||3.1 (1.0)||3.6 (0.8)***||3.0 (0.8)|
|Encourages self-directed learning||3.7 (0.7)***||3.1 (0.9)||3.8 (0.8)***||3.2 (0.9)||3.7 (0.8)***||3.2 (1.0)||3.8 (0.7)***||3.1 (0.8)
||*** p<.0001, ** p<.01, * p<.05.|
§ p<.01 for difference in the mean responses of CBL and PBL between YR2 & YR 3 students.
Our results are consistent with the small amount of prior research (Srinivasan et al., 2007; Williams, 2005). More than half of those surveyed felt that PBL did not make efficient use of time, which was a major reason for its rejection by the time-constrained students (Srinivasan et al., 2007; Tarnvik, 2007). Apart from this, only 10-20% felt that PBL had less unfocussed discussions and provided opportunities to apply knowledge and skills to cases. Interestingly, while gender preferences for learning styles are well-documented in literature (Peplow, 1998), our results show no significant difference between the opinion of males and females, with 78% of both groups preferring CBL over PBL.
As reflected in our results, while both second and third year students found CBL to be time-efficient and having fewer unfocussed discussions, the third year students supported it more strongly. This was probably attributable to reasons, including unproductive or tangential discussions leading to inefficient use of time, which these students had experienced more due to a longer PBL exposure, having had experienced the ill-structured PBL environment, which facilitation was not necessarily able to overcome. Also, since the third year is perceived to be the busiest pre-clinical year in this course, and the students had matured over time, they were probably better able to perceive the efficacy of either mode of study. Interestingly, the second year and male students did not perceive any difference between PBL and CBL with respect to tutor participation and feedback. This may be primarily due to the interactive and nurturing relationship between the tutors and the second year students, which was more guided than the traditional PBL curriculum, in order to relieve stress and provide reassurance to the students.
While self-directed learning has been promoted as a primary strength of the PBL process in academic literature (Albanese & Mitchell, 1993; Dolmans et al., 2005; Norman & Schmidt, 2000; Schmidt, 1983), only 37% of our students agreed with the statement that PBL encouraged self-directed study. Both second and third year students perceived CBL to be more self-directed than PBL (p<.001), and so did males and females. This may in part be attributable to the fact that the learning material was provided to the students in both the methods, hence reducing the opportunity for students to seek their own resources in PBL. Also, the tutors were accessible for answering questions and providing guidance after the PBL sessions. The students probably felt more in control of, or more motivated towards their learning and thus considered it to be self-directed. In spite of this, the students considered CBL to make efficient time use and encourage the application of knowledge and skills while promoting discussions and clinical problem solving. This indicates that the mode of learning needs to provide a motivator for learning and this may be more important than pure self direction.
The major reasons identified for the relative popularity of CBL were its structured format which encouraged time-efficiency, participation, development of clinical problem solving skills and the opportunity to apply skills to cases (Srinivasan et al., 2007; Williams, 2005). CBL offers security to students due to its teacher-directed approach and well-structured learning (Tarnvik, 2007). In CBL, the learning process is a shared responsibility of both tutors and students (Srinivasan et al., 2007). Being teacher-directed, the learning outcomes are pre-defined by the unit co-ordinator, and the students are able to make efficient use of time by consolidating their newly acquired knowledge and clarifying doubts through focussed case discussions (Tarnvik, 2007; Williams, 2005). The CBL structure also offers inquisitive and well-prepared students the opportunity to exploit the full potential of the expert tutors, and gain an insight into their clinical experiences (Srinivasan et al., 2007; Tarnvik, 2007; Williams, 2005). For the time-pressured medical students, CBL thus offers a more efficient use of time while achieving the same learning outcomes as PBL (Katsikitis et al., 2002; Srinivasan et al., 2007).
This is in stark contrast to PBL, and possibly the reason for PBL's rejection by the students. The various limitations of PBL include the constant dilemma faced by students of identifying learning needs, while receiving no correction from the tutors, loss of valuable time in unfocussed and tangential discussions and unresponsive participants due to group dysfunction (Srinivasan et al., 2007; Tarnvik, 2007; Williams, 2005). Since the undergraduate students are still in their formative years of knowledge acquisition, they are not able to assume full responsibility of regulating their learning processes themselves, and it can be a very stressful experience for them (Dolmans et al., 2005; Tarnvik, 2007). Also, while the lack of correction by the PBL tutor is considered to encourage curiosity and lifelong learning, it can cause tremendous tension for the learners who are seeking reassurance (Raidal & Volet, 2009). It is also argued that passivity from the tutor may lead the students to form wrong conclusions which in turn would lead to a critical inability to correctly apply knowledge in the clinical setting (Albanese & Mitchell, 1993; Srinivasan et al., 2007; Williams, 2005). As such, PBL students have been reported to have a tendency for higher resource use per patient, which may be due to a perceived difficulty in arriving at a diagnosis (Albanese & Mitchell, 1993). Also, most authors have reported PBL students to be more likely to have an incomplete or wrong understanding in their prior knowledge, as reflected by a trend towards a lower basic science test scores (Albanese & Mitchell, 1993). This may also be explained by a reported small negative effect size of self-directed and self-paced learning in PBL (Norman & Schmidt, 2000), while students in more directive forms of PBL programs scored higher in the same exam than those in the conventional system (Albanese & Mitchell, 1993). Additionally, since mature age students and top performers are more likely to have the skills to undertake more self-regulated learning as compared to young learners who require and appreciate more regulation from tutors, it would be best to reserve the use of PBL for post-graduate education (Raidal & Volet, 2009; Tarnvik, 2007).
While the collaborative approach in PBL encourages team-work and division of labour amongst students (Albanese & Mitchell, 1993), this is quite different to the CBL study environment, where students are expected to prepare all outcomes of a topic individually. It has been argued that the PBL graduates become dependent on other members of the group for problem-solving and reaching a consensus, and thus struggle in the real world when expected to take independent decisions, due to a greater desire for affiliation (Albanese & Mitchell, 1993). Though, research reporting on the effectiveness of CBL in this respect could not be identified, it would be more reasonable to expect that CBL graduates would be more independent and confident decision-makers, primarily due to its structure.
CBL is advocated as a valuable strategy for teaching abstract issues like morals and ethics and effectively depicting various situations where theory is applicable, thus showing the practical application of the theoretical knowledge and improving analytical skills (McNaught et al., 2005; Tarnvik, 2007). Students have also valued the longitudinal CBL cases over other didactic methods due to the extensive follow-up which they provided, thus creating a simulated student-patient continuity, which would never be achieved through their limited clinical exposure (Struck & Teasdale, 2008).
Though this study has considered an important aspect of student learning in higher education, and has a good sample size (n=255), it is not without limitations. The students were surveyed after just 6 weeks of exposure to CBL which is a relatively short time period for them to experience and absorb a new learning style, and evaluate it in-depth. With the passage of time and through a refinement of the process, there may have been an additional, or lesser, support for either method. Furthermore, due to the paucity of time and resources, intensive training of the tutors could not be implemented and so they may have had an ill-defined understanding of their roles. Due to this, some of the tutors were found to struggle with their newly defined role in CBL. Also, due to the limited scope of this study, not much can be commented on the differences between PBL and CBL in terms of clinical reasoning or problem solving skills acquired from the exposure and the long term effects in terms of recall, application of knowledge and independent learning, for which further research is warranted.
Despite these short comings, a revival of interest towards the implementation of the CBL method in medical education is expected. CBL has gained renewed prominence in other disciplines such as law, business and engineering as it is a sustainable interactive mode of learning. It is a time and cost-efficient alternative to PBL for effectively using the limited resources in educational and clinical practise, while stimulating independent student learning (Tarnvik, 2007). Research has shown CBL to make superior use of the resources and achieve the same outcomes as PBL, in a third of the time and with no significant difference in outcomes of students' examination results or their ratings of their tutors (Katsikitis et al., 2002). Concordantly, our research demonstrates that students perceive CBL to be capable of achieving most of the beneficial outcomes of PBL, including the most critical feature of encouraging autonomous learning in a shorter time.
Nonetheless, a major challenge faced by a group-based curriculum at any university is the perception of students coming from different learning backgrounds and orientations, especially international students who may have probably never been exposed to such forms of social learning. The interactive demands placed on students by these small-group modes of learning may cause them to experience difficulty in adapting to this new curriculum and may potentially cause a barrier to effective learning, as the learning style may not directly conform to the students' conceptions and regulation of learning (Raidal & Volet, 2009). In our experience, complementing lectures with CBL helped to prime all the students and thereafter encouraged them to prepare independently and explore the study topics through active discussions under the tutors' guidance.
In the paucity of sufficient research which elaborates on the optimum balance between teacher-directed and student-centric modes of learning, opting to adhere to the middle path as recommended by Albanese seems to be the best choice (Albanese & Mitchell, 1993). He suggests that an appropriate curriculum would be such that it is able to include the benefits of PBL and didactic lectures, while providing students the opportunity to investigate clinical cases aligned with their basic knowledge (Albanese & Mitchell, 1993). He also advocates the teacher-directed approach in early medical education as it produces efficient learning and student satisfaction. (Albanese & Mitchell, 1993). CBL complemented with lectures fits into this definition accurately. It draws on the strengths of the didactic approach in the early formative years of background knowledge which equip the students with a thorough understanding of the basic concepts. Thereafter, CBL proceeds by encouraging learners to apply and reinforce their freshly acquired knowledge by relevant discussions and applications (Tarnvik, 2007).
Interestingly, PBL graduates rate themselves as well prepared as conventional graduates especially in problem solving, collaboration, self-evaluation, independent learning skills and handling patients, even though they consider their basic science preparation comparatively weaker (Albanese & Mitchell, 1993). They are also found to perform better in clinical examinations and have higher clinical ratings by their clinical supervisors (Albanese & Mitchell, 1993). Is this attributable to the unique features of group processes and not exclusive to the PBL experience? If this is the case, then the potential for group based processes, like CBL, to achieve the same outcomes in student learning is very real and should be explored further than has been done to date, thereby avoiding an overreliance on one teaching and learning method in medicine.
Albanese, M., & Mitchell, S. (1993). Problem-based learning: A review of literature on its outcomes and implementation issues. Academic Medicine, 68(1), 52-81.
Barrows, H. S. (1986). A taxonomy of problem-based learning methods. Medical Education, 20, 481-486.
Colliver, J. A. (2000). Effectiveness of problem-based learning curricula: Research and theory. Academic Medicine, 75(3), 259-266.
Dolmans, D. H. J. M., De Grave, W., Wolfhagen, I. H. A. P., & Van der Vleuten, C. P. M. (2005). Problem-based learning: Future challenges for educational practice and research. Medical Education, 39, 732-741.
Katsikitis, M., Hay, P. J., Barrett, R. J., & Wade, T. (2002). Problem- versus case-based approaches in teaching medical students about eating disorders: A controlled comparison. Educational Psychology, 22(3), 277-283.
McNaught, C., Lau, W. M., Lam, P., Hui, M. Y. Y., & Au, P. C. T. (2005). The dilemma of case-based teaching and learning in science in Hong Kong: Students need it, want it, but may not value it. International Journal of Science Education, 27(9), 1017-1036.
Norman, G. R., & Schmidt, H. G. (2000). Effectiveness of problem-based learning curricula: Theory, practice and paper darts. Medical Education, 34, 721-728.
Peplow, P. (1998). Attitudes and examination performance of female and male medical students in active, case-based learning programme in anatomy. Medical Teacher, 20, 349-355.
Raidal, S. L., & Volet, S. E. (2009). Preclinical students' predispositions towards social forms of instruction and self-directed learning: A challenge for the development of autonomous and collaborative learners. Higher Education, 57, 577-596.
Schmidt, H. G. (1983). Problem-based learning: rationale and description. Medical Education, 17, 11-16.
Schmidt, H. G., & Moust, J. H. C. (1998). Processes that shape small-group tutorial learning: A review of research. Annual Meeting of the Americal Educational Research Association. San Diego, CA.
Srinivasan, M., Wilkes, M., Stevenson, F., Nguyen, T., & Slavin, S. (2007). Comparing problem-based learning with case-based learning: Effects of a major curricular shift at two institutions. Academic Medicine, 82(1), 74-82.
Struck, B. D., & Teasdale, T. A. (2008). Development and evaluation of a longitudinal case-based learning (CBL) experience for a geriatric medicine rotation. Gerontology & Geriatric Education, 28(3), 105-114.
Tarnvik, A. (2007). Revival of the case method: A way to retain student-centred learning in a post-PBL era. Medical Teacher, 29, e32-e36.
Williams, B. (2005). Case based learning - a review of the literature: Is there scope for this educational paradigm in prehospital education? Emergency Medicine Journal, 22, 577-581.
|Authors: Nita Sodhi-Berry and Helena Iredell, School of Population Health, The University of Western Australia. |
Please cite as: Sodhi-Berry, N. & Iredell, H. (2010). Problem based learning versus case based learning: Students' perceptions in pre-clinical medical education. In Educating for sustainability. Proceedings of the 19th Annual Teaching Learning Forum, 28-29 January 2010. Perth: Edith Cowan University. http://otl.curtin.edu.au/tlf/tlf2010/refereed/sodhi-berry.html
Copyright 2010 Nita Sodhi-Berry and Helena Iredell. The authors assign to the TL Forum and not for profit educational institutions a non-exclusive licence to reproduce this article for personal use or for institutional teaching and learning purposes, in any format, provided that the article is used and cited in accordance with the usual academic conventions.