Jun 11, 2017

Evidence-based medicine and Problem-based learning

In his 1997 article David Sackett on his description of evidence-based medicine states:

The practice of evidence-based medicine is a process of life-long, self-directed learning in which caring for one's own patients creates the need for clinically important information about diagnosis, prognosis, therapy, and other clinical and health care issues, and in which its practitioners:

  1. Convert these information needs into answerable questions;
  2. Track down, with maximum efficiency, the best evidence with which to answer them (and making increasing use of secondary sources of the best evidence);
  3. Critically appraise that evidence for its validity (closeness to the truth) and usefulness (clinical applicability);
  4. Integrate the appraisal with clinical expertise and apply the results in clinical practice; and
  5. Evaluate one's own performance.

Evidence-based medicine is one of several disciplines that has evolved from clinical epidemiology and critical appraisal. Parallel developments, still with the individual patient as the focus of attention, are occurring in other clinical disciplines (eg, evidence-based surgery, evidence-based nursing, evidence-based dentistry). Other evidence-based disciplines consider the community as the focus of attention rather than the individual patient (evidence-based public health), or add an explicit economic element and seek to purchase or provide that mix of health care that will maximize some group or public benefit (evidence-based purchasing).

Notice that the inquiry by the practitioner of evidence-based medicine starts with the concerns of the individual patient. The process of learning in EBM as described by Sackett parallels the iterative process also found in problem-based learning. The following figure, adapted from the book Problem-based Learning in Clinical Education: The next Generation, lists the steps in problem-based learning:

The introductory chapter is comprehensive, but here I will only list a few points I consider important features of problem-based learning as described by Hmelo-Silver and Eberbach:

  • PBL is a learner-centered instructional method in which students learn through solving ill-structured problems (Barrows, 2000; Hmelo-Silver, 2004; Torp & Sage, 2002). Students work in collaborative groups to identify what they need to learn in order to solve a problem. They engage in self-directed learning and then apply their new knowledge to the problem and reflect on what they learned and the effectiveness of the strategies employed. Goals of PBL include helping students develop (1) flexible knowledge, (2) effective problem-solving skills, (3) effective self-directed learning skills, (4) effective collaboration skills, and (5) intrinsic motivation.

  • Discussing problems in a PBL group (prior to researching learning issues) activates relevant prior knowledge and facilitates the processing of new information (Schmidt, DeGrave, DeVolder, Moust, & Patel, 1989). Students can better construct new knowledge when they can relate it to what they already know.

  • Metacognitive skills refer to the executive control processes of planning one’s problem solving, monitoring one’s progress, and evaluating whether one’s goals have been met (Schoenfeld, 1985).

  • Metacognitive strategies are also important for the third goal of developing lifelong learning skills: being a self-regulated learner (Ertmer & Newby, 1996; Zimmerman, 2002). There are several processes involved. First, learners must have a metacognitive awareness of what they do and do not understand. Second, they must be able to set learning goals for themselves, identifying what they need to learn more about for the problem they are solving. Third, they must be able to plan how to achieve their goals. Finally, as they implement their plan, learners must evaluate whether or not their goals have been attained.

  • At several points in the problem, students typically pause to reflect on the data they have collected so far, generate questions about that data, and hypothesize about underlying causal mechanisms that might help explain it. The students then identify concepts they need to learn more about in order to solve the problem (i.e., ‘‘learning issues’’). After considering the problem with their naive knowledge, the students divide and independently research the learning issues they have identified. They then regroup to share what they learned, reconsider their hypotheses and/or generate new hypotheses in light of their new learning, as shown in the cycle (Fig. 1.1). When completing the task, learners reflect on the problem in order to abstract the lessons learned, as well as how they performed in self-directed learning and collaborative problem solving. They evaluate their understanding of the problem as well as their progress toward a solution.

  • A more general cognitive analysis of PBL suggests that as students are presented with problems, they access prior knowledge, establish a problem space, search for new information to help reach their problem-solving goals, and in the process, they may construct new mental representations or restructure existing representations that include the conditions in which the knowledge might be used (Anderson, 1982). This process involves developing metacognitive awareness of one’s progress on both learning and problem solving (Hmelo & Lin, 2000).

    Hmelo-Silver and Eberbach., "Chapter 1." Problem-based Learning in Clinical Education: The next Generation., 2014.
  • Howard Barrows had a great insight about activities that do not promote learners to become independent and this is one of them:

    Case histories and case vignettes containing succinct and complete databases are used extensively in the teaching and evaluation of medical students. The clinicians who wrote these cases had to generate appropriate initial hypotheses about the patient’s problem, as it initially presented, and carry out an appropriate inquiry to assemble the significant and relevant data for the case write-up. As a result, this important and often difficult aspect of reasoning has already been performed for the student. For undergraduate students who must learn to inquire logically in an effective and efficient manner, this use of case vignettes or complete cases may be worse than spoon-feeding. A teacher at the Harvard Business School, where the ‘case method’ has flourished over the last half century, identified the same problem with their use of cases. He expressed the concern that when their students entered the real business world after graduation no one would give them a case when they were confronted by a problem and they would not know how to obtain the data they needed to build their own case.

    The practice of evidence-based medicine, as originally described by David Sackett, entails the same set of skills as those found in problem-based learning. The goal of these skills in the right environment is the development of an independent and adaptable learner.

    No comments:

    Post a Comment

    1. You should attempt to re-express your target’s position so clearly, vividly, and fairly that your target says, “Thanks, I wish I’d thought of putting it that way.
    2. You should list any points of agreement (especially if they are not matters of general or widespread agreement).
    3. You should mention anything you have learned from your target.
    4. Only then are you permitted to say so much as a word of rebuttal or criticism.
    Daniel Dennett, Intuition pumps and other tools for thinking.

    Valid criticism is doing you a favor. - Carl Sagan