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Biomedical subjects

G R Norman

Publications and source records attributed to G R Norman.

At least 19 recordsLinked to original sources

The psychological basis of problem-based learning: a review of the evidence.

Several potential advantages for students' learning are claimed for problem-based learning (PBL). Students in PBL curricula may be more highly motivated; they may be better problem solvers and self-directed learners; they may be better able to learn and recall information; and they may be better able to integrate basic science knowledge into the solutions of clinical problems. Although some of these claims find theoretical support from the literature on the psychology of learning, to date there has been no review of the experimental evidence supporting the possible differences in students' learning that can be attributed to PBL. In this review article, the authors examine each claim critically in light of that evidence. They conclude that (1) there is no evidence that PBL curricula result in any improvement in general, content-free problem-solving skills; (2) learning in a PBL format may initially reduce levels of learning but may foster, over periods up to several years, increased retention of knowledge; (3) some preliminary evidence suggests that PBL curricula may enhance both transfer of concepts to new problems and integration of basic science concepts into clinical problems; (4) PBL enhances intrinsic interest in the subject matter; and (5) PBL appears to enhance self-directed learning skills, and this enhancement may be maintained.

Curriculum

The correlation of feature identification and category judgments in diagnostic radiology.

Expert and novice radiologists were given films accompanied by clinical histories that supported a diagnosis either of bronchiolitis or of normal. To provide a plausible task context, some films were radiologically unambiguous and were accompanied by histories consistent with them. For a set of radiologically difficult films from confirmed normal or bronchiolitis patients, fictitious normal or abnormal histories were counterbalanced with the films. The clinical histories affected ratings both of diagnosis and of features present on the difficult films. Thus, uncertainty about individual features evidently was affected by history, and features did not act as an independent source of information. The dependence of feature calls on an overall judgment was also suggested by intra-observer agreement in another study in which an explicit diagnosis was not requested. It is unclear whether the history increased discrimination between normal and abnormal films, or indiscriminately added evidence for or against the disease. Factors are discussed that make it appropriate for feature identification to be partially dependent on category identification.

Attention

Role of specific similarity in a medical diagnostic task.

Three experiments are reported showing that diagnosis of skin disorders by medical residents and general practitioners was facilitated by similar cases previously seen in the same context. Diagnosis of similar cases was facilitated more than that of dissimilar cases in the same diagnostic category, demonstrating that facilitation was not solely due to activation of the diagnostic category as a whole. Because diagnosis was posed in a multiple-choice format that always included the correct diagnosis, the relative disadvantage of dissimilar items was not due to the unavailability of the category name. The similarity effect also occurred with 2-week delay between the initial case and the test cases. Variations in diagnostic procedure, ranging from giving a quick first impression to arguing for given alternative diagnoses before selection, did not interact with the effect of similarity. This result suggests that the similarity effect is not strongly dependent on a particular diagnostic strategy.

Adult

Effects of conventional and problem-based medical curricula on problem solving.

This study examined the reasoning processes of beginning, intermediate, and senior students in two medical schools with different curricular formats. One school had a conventional curriculum (CC) where basic science was taught one and a half years before the clinical training, and the other had a problem-based learning curriculum (PBLC) where basic science was taught in the context of clinical problems and general problem-solving heuristics were specifically taught. The students were asked to give diagnostic explanations of a clinical case, both before and after being exposed to relevant basic science information. Two distinct modes of reasoning were identified, each reflecting a curriculum type. A predominantly "backward-directed" hypothetico-deductive mode of reasoning was found in the explanations of the PBLC students, and a "more forward-directed" pattern of reasoning was found in the explanations of the CC students. Students in the PBLC produced extensive elaborations using relevant biomedical information, which was relatively absent from the CC students' explanations. However, these elaborations were accompanied by a tendency to generate errors. These results have important implications regarding the strengths and weaknesses of the two types of curricula.

Canada

Pitfalls in the pursuit of objectivity: issues of reliability.

Objectivity has been one of the hallmarks in the assessment of clinical competence in recent decades. A consistent shift can be noticed in which subjective measures are being replaced by objective measurement methods. In the transition from subjective to objective methods trade-offs are involved, both in the effort expended and in the range of behaviours assessed. The issue of the presumed superiority of objective measures is addressed in two successive papers. In this paper a distinction is made between objectivity as a goal of measurement, marked by freedom of subjective influences in general, and objectivity as a set of strategies designed to reduce measurement error. The latter has been termed objectification. The central claim of this paper is that these two approaches to assessment do not necessarily coincide. By reviewing a number of studies comparing subjective and objectified measurement methods, the claim of the supremacy of the latter with respect to reliability is discussed. The results of these studies indicate that objectified methods do not inherently provide more reliable scores. Objectified methods may even provide unwanted outcomes, such as negative effects on study behaviour and triviality of the content being measured. The latter issues, related to validity, efficiency and acceptability, are discussed in a second paper.

Achievement

Pitfalls in the pursuit of objectivity: issues of validity, efficiency and acceptability.

In a previous article the distinction is made between objectivity and objectification. Objectivity is considered a generic goal of measurement, marked by freedom of subjective influences in general, whereas the latter term is used to describe strategies to reduce measurement error. A survey of several studies indicated that objectified methods are not intrinsically more reliable than subjective measures. In this paper the consequences of objectification are analysed for issues related to validity, efficiency, transparency, and effect of these methods on students and teachers. Several studies comparing objectified and subjective methods are surveyed for this propose. The studies indicate that--as in the previous article on reliability--objectification and objectivity are not identical, and that there are many pitfalls in the objectification of measurement procedures. As a consequence, it is argued that objectified methods should not exclusively be chosen on the basis of their unconditional appeal to objectivity, but that the application of measurement methods should follow the specific purpose of the testing situation. In the context of the testing situation, arguments against and in favour of objectification should be weighted, and trade-offs are to be evaluated. The outcome of this evaluation may vary from situation to situation, and from institution to institution.

Achievement

Evaluation of graduating neonatal nurse practitioners.

To compare the knowledge and problem-solving, communication, and clinical skills of graduating neonatal nurse practitioners (NNPs) and pediatric residents, a cohort study was conducted in a 33-bed tertiary-level neonatal intensive care unit in a 400-bed teaching hospital affiliated with a faculty of health sciences. Participants were all (n = 10) NNP graduates from the first 3 years of the educational program and 13 (87%) of 15 second-year pediatric residents. One hundred multiple-choice questions and 20 radiographic slides were used to test knowledge; a semistructured oral examination tested problem-solving skills; three simulated interactions with parents tested communication skills; and seven simulated procedures tested clinical skills. Graduating NNPs scored similarly to the pediatric residents on the multiple-choice questions (difference -3.4%; 95% confidence interval [CI] around difference -9.7, 2.9), radiographs (difference -1.4%; 95% CI -11.5, 8.7), oral examination (difference 2.8%; 95% CI -11.1, 16.7), communication skills (simulated parents assessment: difference 0.8%; 95% CI -4.2, 5.7; expert observer assessment: difference 5.8%; 95% CI -2.8, 14.3), and clinical skills (difference 7.4%; 95% CI -5.5, 20.2). The NNPs about to graduate from their educational program showed knowledge and problem-solving, communication, and clinical skills equivalent to those of second-year pediatric residents and are thus likely to deliver comparable care in the clinical setting. The results support the adoption of the NNP role.

Clinical Competence

Charting the winds of change: evaluating innovative medical curricula.

The increased interest, in North America and around the world, in problem-based and community-oriented medical curricula has sparked interest in the evaluation of these innovative programs. In January 1989, the Josiah Macy Jr. Foundation sponsored a conference to consider designs for evaluation studies and the potential distinctive outcomes of the innovative curricula that might be foci of these studies. After defining an "innovative curriculum," the participants identified seven characteristics of "important evaluation studies," particularly endorsing studies that compare curricula as whole entities. The participants then identified 26 areas where differences between graduates of innovative and traditional curricula might be expected, and five equally important areas where differences are not expected. Distinctive outcomes of innovative curricula were anticipated in areas such as interpersonal skills, continuing learning, and professional satisfaction. Overall, these recommendations are offered to stimulate creative evaluations of the growing number of innovative programs in medical education.

Clinical Clerkship

A cognitive perspective on medical expertise: theory and implication.

A new theory of the development of expertise in medicine is outlined. Contrary to existing views, this theory assumes that expertise is not so much a matter of superior reasoning skills or in-depth knowledge of pathophysiological states as it is based on cognitive structures that describe the features of prototypical or even actual patients. These cognitive structures, referred to as "illness scripts," contain relatively little knowledge about pathophysiological causes of symptoms and complaints but a wealth of clinically relevant information about disease, its consequences, and the context under which illness develops. By contrast, intermediate-level students without clinical experience typically use pathophysiological, causal models of disease when solving problems. The authors review evidence supporting the theory and discuss its implications for the understanding of five phenomena extensively documented in the clinical-reasoning literature: (1) content specificity in diagnostic performance; (2) typical differences in data-gathering techniques between medical students and physicians; (3) difficulties involved in setting standards; (4) a decline in performance on certain measures of clinical reasoning with increasing expertise; and (5) a paradoxical association between errors and longer response times in visual diagnosis.

Clinical Competence

Issues in the use of change scores in randomized trials.

The literature on the measurement of change is often confusing and contradictory. Some authors advocate the use of change scores as the best approach to the analysis of treatment effects in clinical trials; others maintain that change scores should be avoided entirely. This paper reviews these arguments and demonstrates that contradictions arise in part from different definitions of change, and in part from some misunderstanding of the relationship between reliability and responsiveness to change. Conditions under which it is, and is not appropriate to use change scores in experimental designs are specified, and formulae for sample size calculations are introduced.

Analysis of Variance

Recall by expert medical practitioners and novices as a record of processing attention.

Using recall of clinical protocols as a measure of expertise in medicine has yielded disappointingly small effects. Experiments using recall of clinical laboratory data are presented to provide an explanation. In one experiment, subjects either deliberately memorized or first diagnosed and then were incidentally asked for memory. With incidental instructions, experts recalled over twice as much data as did students, but with memorization instructions, student performance approximated that of experts. Experts also showed a large advantage over students in incidental recall of data that were not relevant to the problem solution. These results suggest that expert processing in this "discrete, independent inputs" domain requires effortful analysis with minimal reliance on default values, rather than relatively effortless pattern perception reported in highly visual areas of expertise. For this area, intentional memory is a misleading measure of expertise. However, incidental memory is a valuable measure of processing during diagnosis.

Adult

Generalizability of grip strength measurements in patients with tennis elbow.

The purpose of this study was to determine the interrepetition and interoccasion generalizability of grip strength measurements in patients with the diagnosis of proximal extensor carpi radialis brevis tendinitis. Thirty-five consecutive patients (mean age = 44.5 +/- 8.6 years; mean duration of symptoms = 3.9 +/- 3.5 months) fulfilling the eligibility criteria participated in the study. Measurements of pain-free grip strength and maximum grip strength for the involved limb and maximum grip strength for the uninvolved limb were taken on two test dates within seven days of each other. We calculated the variation between measurements within a test session and the variation from one session to the next using generalizability coefficients based on the mean of the six measurements. The coefficients for interrepetition, interoccasion, and overall generalizability were .99, .97, and .96, respectively. The clinical implication of these findings is that the overall generalizability can best be enhanced by averaging grip strength measurements recorded from multiple test sessions rather than by increasing the number of repetitions during a single test session.

Adult

The development of expertise in dermatology.

To examine the development of expertise in dermatology, accuracy of diagnosis and response times of subjects at five levels of expertise were assessed. A total of 100 slides, 2 typical and 3 atypical slides from each of 20 common skin disorders, were presented to six subjects at each of the following levels: second-year preclinical medical students, final year medical students, residents in family medicine, general practitioners, and dermatologists. Accuracy of diagnosis rose from 21% for medical students to 87% for dermatologists. Correct diagnosis was associated with a decrease in response time with expertise, whereas errors were associated with a dramatic increase in response time, and was slower than correct response times at all levels, suggesting that errors do not result predominantly from carelessness or speed. Typical slides accounted for a constant proportion of diagnostic errors at all higher levels of expertise, and experts continued to make a significant proportion of errors on slides shown to be relatively easy for residents. The results are shown to be at variance with any model that equates expertise with the mastery of complex rules, but they are consistent with models of expertise that propose that expertise is equated with a rapid "pattern-recognition" process, and errors result from unintended confusion with previous similar examples.

Dermatology