TOWARD SCIENCE-BASED INSTRUCTION: LESSONS FROM AN INTRODUCTORY SOILS COURSE

Unlike science-based research, some teaching strategies lack robust empirical support. We conducted an experiment as part of the laboratory component of an introductory soils course to explore the effects of peer instruction on student learning outcomes. Here, we describe results of two instructional interventions (pilot, experimental). Students were randomly assigned to either control or treatment groups. While members of both groups completed pre- and post-tests, control subjects followed standard laboratory procedures whereas treatment subjects were responsible for teaching the subject matter and procedures to their peers. Post-test scores for both the pilot and experimental studies were significantly higher than pre-test scores (p<0.05), both for control and treatment groups. This implies the standard laboratory procedure improved student learning. Gains (post-test minus pre-test scores), however, were ~20% greater for treatment groups, suggesting a greater learning outcome return on the minimal additional time investment (~10 minutes within a 110-minute laboratory session). We also found that the post-test score variances for treatment—but not control—groups were greatly reduced: interquartile ranges decreased by ~60%. This could be an overlooked learning outcome benefit if one of the essential elements of effective teaching is addressing student misconceptions. We also explored the effects of different TAs, different laboratory sessions, and covariates such as subject GPA. This work provides a template for rapid geoscience education interventions that promote improved learning outcomes.