Explicit Instruction about the Nature of Science and its Impact on Students’ Understanding of Evolution: A Meta-Analysis

Understanding evolution remains a persistent challenge in science education. This meta-analysis evaluated whether explicit instruction on the Nature of Science (NOS) can enhance students’ comprehension of evolutionary theory. A systematic review following PRISMA 2020 guidelines identified eight studies (2017–2024), yielding nine independent effect sizes and a total sample of 1,543 students across secondary and undergraduate levels. Using a random-effects model, the overall effect of explicit NOS instruction was large and statistically significant (Hedges’ g = 1.18, 95% CI [0.698, 1.669], p < .001). Moderator analysis showed that educational level significantly influenced outcomes, with secondary students benefiting more than undergraduates. A Two One-Sided Tests (TOST) procedure confirmed that these differences were not practically equivalent within a ±0.20 margin. Qualitative synthesis revealed that the most effective interventions explicitly addressed NOS concepts, such as theory vs. law, empirical evidence, and subjectivity through historical case studies and structured reflection designed to counter evolution misconceptions. No evidence of publication bias was detected. These findings underscore the pedagogical value of embedding epistemological instruction within evolution education and support the development of context-sensitive curricula and teacher training.