Topic Priorities and Assessment Participation in Comparisons of Four Materials Teaching Approaches

Comparative judgments about materials teaching depend on the knowledge assessed and the students represented at assessment. This study examines lecture, discussion, discussion with sketching, and discussion with sorting through five Materials Concept Inventory items in four undergraduate cohorts. The analysis calculates percentage-point changes, normalized gains, item-omission comparisons, curriculum-weight thresholds, and entering-class endpoint bounds. Mean normalized gains are 36.44%, 39.41%, 69.17%, and 44.80%, respectively. Sketching retains the largest mean after every single-item omission, although the ordering of the other approaches changes. When polymer melting receives increasing weight and the other topics share the remaining weight equally, lecture first overtakes sketching at 78.34% of total weight. Post-assessment coverage ranges from 74.51% to 85.00% of entering enrollment. Allowing unobserved students any endpoint score between zero and full correctness produces overlapping ranges for most comparisons. An apparent 0.68-point separation between sketching and sorting also disappears after allowance for whole-percentage rounding. These findings distinguish stable advantages within the selected assessment from conclusions that depend on curriculum emphasis or response completeness. Because each approach occurs in only one cohort and pre/post responses are unlinked, the results describe class differences rather than causal teaching effects. The practical implication is to evaluate teaching choices against explicit topic priorities and a clearly defined student denominator.