Systems Thinking with Causal Loop Diagrams in Medical Education: An Exploratory Study

Medical literature is replete with diagrammatic representations of systems, yet lacks standardised nomenclature and consistent symbolic conventions. In an introductory system dynamics course for health science students, causal loop diagrams (CLDs) are used to support systems thinking. Notwithstanding recognised limitations, CLDs provide a coherent heuristic for representing multivariate systems with feedback. We studied 55 first-year volunteers enrolled in the course to compare understanding of systems presented as CLDs versus typical journal diagrams. Two endocrine systems were selected from open-access, peer-reviewed literature: calcium homeostasis and glucose homeostasis. Participants were shown either the original journal diagram for one system and a CLD for the other, or vice versa, and answered twelve true/false questions—six per system. A mixed-model, two-way repeated measures ANOVA revealed a significant interaction between Diagram (CLD vs. journal diagram) and System (Calcium vs. Glucose). Post hoc comparisons showed significantly higher performance with CLDs for both Calcium (0.84 vs. 0.38) and Glucose (0.83 vs. 0.63), p < 0.001. A Fisher’s Exact Test also indicated a higher proportion of questions favouring CLDs. These findings suggest that training in CLDs may enhance understanding of complex systems compared to standard journal diagrams. Further work is needed to address limitations including the small sample size, use of a single cohort, and a restricted set of diagrams.