Answer to "What is ‘pure’ PBL and what is ‘hybrid’ PBL?"

Barrows and Tamblyn’s (1980) original conception PBL can be described as ‘pure’ PBL and was characterised by: 

  • No learning outcomes provided. Guided by the tutor (a clinician) who was a process but not a content ‘expert’*, a small group of students identified what was needed to learn to return and explain the ‘problem’. The ‘patient’ or ‘problem’ came first and thus drove their learning.

  • Few formal face-to-face sessions relating to the content of the PBL case (i.e. the learning issues identified) were scheduled. Experts were, however, available for consultation, and, if the cohort needed assistance with a concept, formal sessions could be requested.

*The original conceptualisation of a non-content expert tutor was a clinician who was tutoring a case or curriculum unit outside of his/her clinical expertise, e.g. an orthopaedic surgeon in an Obstetrics and Gynaecological block. The purpose of this was to prevent the tutor from reverting to old habits of content delivery.


Due to the widespread adoption of PBL in undergraduate medical programmes (and thus the need to support learners’ transition to university and to a new learning approach), it is unlikely that ‘pure’ PBL exists today. It is more common to read about ‘hybrid’ PBL in which faculty offers learners resources and activities to support and supplement their self-study. In 2009, Kwan and Tam identified four subtypes of ‘hybrid’ PBL, ranging from Type I, with a few PBL cases during the year to situations which most of us would describe as ‘hybrid’ PBL (Type IV), i.e. the learning is driven by the PBL problems with students supported by judiciously prepared interactive sessions that to provide direction and to enrich their self-study. For Lim (2012), this Type IV ‘hybrid’ PBL is probably now ‘standard’ PBL and ‘hybrid’ PBL should then include curricula incorporating PBL-style tutorials but not fitting the criteria for standard PBL (i.e. PBL problems are not centre-stage in terms of curriculum delivery).  These deliberations highlight the extent to which PBL has been customised over the years, and which has led to confusion about what is and what is not PBL. This customisation has also clouded the evidence around the intended educational outcomes of PBL as an educational approach.


In Lim’s (2012) now ‘standard’ PBL is characterised by small group discussions around patient problems, followed by the identification of learning issues which are then supported by a few face-to-face sessions covering key concepts or known areas of difficulty to assist students to meet their self-identified learning needs. During PBL cases or problems development, key or threshold concepts should be identified. Through a range of activities such as large group sessions, workshops, practicals and online resources, students are thus supported in meeting their learning needs.  One of the dangers with this approach, however, is that without careful monitoring and appropriate faculty development, these additional sessions may degenerate into information delivery (i.e. traditional didactic lectures), thereby discouraging learners from being responsible for researching the learning issues. If these supplementary sessions ‘solve’ the ‘problem’, then the active inquiry which PBL is purported to foster is undermined. In addition, the reporting phase (after a period of self-study) is then at risk of becoming a regurgitation of ‘lecture’ notes. Similarly, if assessment is blueprinted to the ‘lecture’ content (i.e. the hybrid component) rather than the learning outcomes generated from working through a PBL problem, this too will undermine the PBL philosophy. It is for these reasons that a PBL curriculum needs to be monitored and any new faculty member thoroughly oriented to the philosophy.

For Schmidt and colleagues (2011), characteristics that define PBL today include:

  • Problems serve as triggers

  • Learners collaborate in small groups for part of the time

  • A tutor or facilitator guides their learning

  • The curriculum includes a limited number of ‘lectures’

  • Learning is student-initiated, and,

  • Learners have sufficient time for self-study



BARROWS, H.S. (1996). Problem-based learning in medicine and beyond: A brief overview. (New Dir Teach Learn. 68:3-12).

BARROW, H.S., and TAMBLYN, R.M. (1980). Problem-based Learning: An Approach to Learning. (New York: Springer).

KWAN, C-Y, and TAM, L. (2009). Commentary: hybrid PBL – what is in a name? (J Med Educ. 13:76-83).

LIM, W.K. (2012). Dysfunctional problem-based learning curricula: resolving the problem. (BMC Med Educ. 12:89

MORO, C., & MCLEAN, M. (2017). Supporting students’ transition to university and problem-based learning. (Med Sci Educ. 27:353-361).

SCHMIDT, H.G., ROTGANS, J.I., and YEW, E.H.J. (2011). The process of problem-based learning: what works and why. (Med Educ. 45:792-806)

TAYLOR, D., and MIFLIN, B. (2008). AMEE Guide No. 36. Problem-based learning: Where are we now? (Med Teach. 30:742-763).