Med students respond better to spaced out education strategy for image interpretation

Education can be accomplished in a number of ways. One popular method of teaching is through sheer repetition (the massed method), while others use a learning process spaced out over time (the interleaved method). But which is the most effective for radiologists?

According to a recent study published by the Journal of the American College of Radiology, the interleaved method produces better results than the massed method across the board.

Sherry X. Yan, SB, Columbia University College of Physicians and Surgeons in New York City, and colleagues recruited 40 students—24 in their first year of medical school, 16 in their second year—to participate in the study within the first month of the academic year.

“First-year students were considered naive observers because they had no formal instruction in radiologic image interpretation,” the authors wrote. “The second-year students had informal instruction in chest radiographic interpretation integrated into the medical school curriculum (anatomy, pulmonary medicine). We randomized subjects into two groups matched for age, gender, and year in medical school.”

Each group was shown a PowerPoint presentation featuring six different examples of 12 common radiographic patterns: normal radiograph, bronchiectasis, miliary disease, pneumothorax, lung mass, emphysema, pleural effusion, pneumonia, atelectasis, congestive heart failure, pulmonary fibrosis, and mediastinal mass. The lecture was 43 minutes long.

One of the groups was then taught using the massed method. The other was taught using the interleaved method. Both groups were tested, being asked to identify radiographic findings in 24 chest radiographs that were considered “not subtle.”

Overall, the average score in the interleaved group was 57 percent, and the average score in the massed group was 43 percent.

Looking closer at the data, average scores on material related to recall were 61 percent for the interleaved group and more than 46 percent for the massed group. Average scores on material related to induction were more than 53 percent for the interleaved group and more than 40 percent for the massed group.

“Our study shows that medical students benefit from the spacing/interleaving method of instruction when learning radiology,” the authors wrote. “At present, medical student radiology education at the workstation and in case conferences is inherently interleaved, but the didactic curriculum in the current educational milieu is largely massed, with its orderly progression through imaging by disease and organ system. It is uncertain whether disruption introduced by interleaving in this setting would be desirable. More work is needed to determine whether radiology instruction might benefit from spacing of items to be learned when the material is presented in a lecture format.”

Yan and colleagues noted that second-year students had better scores than first-year students, a finding that was “in line with existing data demonstrating the beneficial effect of old expertise on new knowledge acquisition.”

The authors did say their study had some limitations. For example, “more research in larger groups” is necessary to make a more compelling comparison between the two learning methods. Also, they said first- and second-year medical students were the focus of this particular study, so the results should not be used to make assumptions about higher level trainees such as radiology residents and fellows.