There are clearly some variations in the extent to which PBL approaches are used and different species of PBL is therefore prevalent within curricula. The way the PBL curriculum is designed can be broadly categorized on a continuum ranging from ‘hybrid’ (or ‘adapted’) approaches, also referred to as transitional semi-problem-based curricula to the ‘full’ (or ‘pure’ ‘rigorous’ and ‘authentic’) PBL approaches (Margetson, 1999:359,364; Newman, 2004:13; O’ Grady, 2004:3). Margetson (1998:193), who focuses specifically on PBL for professional practice in the field of medicine, distinguishes between these two main conceptions of PBL as Conception 1 or C1 (which typifies the hybrid approach to PBL) and Conception 2 or C2 (which typifies the full PBL approach). Conception should be understood here as the ideas and ways of thinking one comes to have (Margetson, 1999:360).
A central difference between C1 and C2 lies in the difference between atomistic addition and holistic integration. Atomistic addition in a traditional curriculum is similar to the ‘staircase’ or ‘brick-on-brick’ model whereas holistic integration is similar to the ‘spider-web’ model referred to earlier (Ward & Lee, 2004:73). According to Margetson (1998:194) C1, which is an improvement on the traditional fragmented curriculum, still compartmentalizes knowledge under discrete subject headings although some integration does take place. Within the ‘hybrid’ approach PBL is accordingly implemented in shorter cycles and there is generally less integration of disciplines. The ‘hybrid’ groups generally have at most two subjects in collaboration for the PBL approach and many involve single-subject PBL (Newman, 2004:13).
The view taken of problems in C1 (Hybrid PBL approaches) is that they are obvious and are not themselves problematic but are used simply as a device for a further purpose, namely as ‘convenient pegs’ on which to hang the coat of knowledge-acquisition (in other words ‘basic’ science knowledge). The main task for students is therefore knowledge-acquisition in relation
to the problem. In this conception, the convenience in using a problem lies simply in its motivating effect (Margetson, 1998:196). According to Duch et al. (2003) Hybrid PBL approaches can accordingly be characterized by a non-exclusive use of problem-driven learning in class which include a mixture of separate lecture segments, tutorials or other active learning components (Newman, 2004:13). Floating or peer facilitator models are commonly used within these Hybrid PBL approaches (Duch et al., 2003).
In contrast the full, authentic PBL approaches (C2) have fuller integration of disciplines which can last through repeated weekly cycles as is the case of Maastricht and other medical school models (Das & Das, 2002:162). The view taken of problems in C2 focuses on a ‘growing web’ of understanding in practice where medical practice is conceived of as an integrated, coherent activity where the practice is developed as a whole (Margetson, 1998:199). In its “pure” or “authentic” form relevant problems are thus introduced at the beginning of the instruction cycle and used to provide the context and motivation for the learning that follows (O’ Grady, 2004:3). The role of a problem in C2 is thus to provide the focus within the rich context in which medical issues arise (Margetson, 1998:197). The conception of the growing web therefore acknowledges that action and practice are necessarily related to understanding. Problems are thus more than they seem on the surface. They are not simple ‘givens’ but may depend on the contexts in which they occur (ibid.:196,359).
According to Margetson (1998:196) Hybrid PBL approaches (C1) can be seen as being a transition case, lying between a traditional conception and a transformed education represented by C2 and must therefore be valued as transitions and not as something they are not. Although the traditional curriculum is improved significantly through C1, it is however still partly trapped in a discredited conception of learning. However, there are contexts in which C1 Hybrid PBL approaches prove to be the better approach such as is the case of The University of the Witwatersrand. The University of the Witwatersrand (Wits) created a Hybrid PBL approach by combining formal lectures with small discussion groups. They argue that due to the poorer academic skills of the foundation year students the Hybrid PBL approach proved to be appropriate since the students still need to be provided with a good knowledge base (a ‘convenient peg’ approach) at this level while simultaneously being required by the simulation games to develop and display the acquired skills encompassed in PBL (Ala & Hyde-Clarke, 2006:123). They propose that PBL can be an excellent teaching
and learning tool at the foundation course level if the course is well conceptualised and scaffold and that it has the capacity to impart essential skills to first-year students who are under-prepared for tertiary study (ibid.:121).
Williams (2001b:254) takes a similar approach to that used at Wits. She has not fully embraced the “full” medical school approach to PBL because the students that she teaches lack the necessary ability and confidence in their problem-solving and physics and mathematical skills. Williams uses condensed mini-presentations that introduce physics principles and integrate the learning units. After acquiring increased confidence in their conceptual understanding of the physics principles, the students then use the PBL process as described by Barrows to work through and solve the real-world problem encountered in each learning cycle (ibid.:256).
2.4.5 Conclusion
It is clear that integration can come in many forms, and that there is no universal PBL approach (Drake, 1998:95; Van Loggerenberg-Hattingh, 2003:53). Similar to Newman (2004:14) the researcher could find no single unanimous position about the theoretical basis for, or practice of, problem-based learning. There is not even agreement about whether there is or should be one type of problem-based learning or many variants. PBL can therefore be implemented within one discipline or at any of the levels of integration (Van Loggerenberg- Hattingh, 2003:53) as identified by Harden (2000:551) depending on the theoretical background for its implementation and the structural and pedagogical context into which it is placed (Poikela & Poikela, 1997:8; Savin-Baden, 2000:19). Kysilka (1998:206-207) also highlighted the fact there is no one ‘best’ organizational structure for curriculum integration and that the integration continuum should not be viewed as a means of forcing teachers to reorganize their curriculum to a ‘best’ approach but that it should rather be viewed as a vehicle to help teachers rethink what they are currently doing in order to improve their current teaching practices to foster learning. It also became apparent that when choosing between PBL approaches such as Hybrid or Pure approaches factors such as class size, the intellectual maturity of students, student motivation, the course learning objectives, the instructor’s preferences and in some institutions, the availability of peer facilitators need to be considered (Duch et al., 2003). Since the success of any curriculum restructuring effort lies within the teacher’s acceptance of that particular curriculum (Ensor, 2001) it is important to pay special
attention to all the factors that are involved in the design and implementation of a PBL curriculum.