Novick and Catley computed composite evolutionary relatedness scores to assess student understanding by averaging across accuracy (0, 1) and explanation quality (0, 0.5, 1).
Students received a score for accuracy (0 or 1) and for explanation quality (0, 0.5, or 1) for each evolutionary relatedness question.
Composite scores (mean of accuracy and explanation quality) were then calculated across the two questions testing each aspect of understanding evolutionary relatedness (different levels and polytomy).
Yet, only 15% of stronger-biology-background students received both an accuracy score of one and an explanation quality score of one across the two questions.
Eight coding categories were arranged from most to least indicative of student comprehension (i.e., in decreasing order of sophistication), and each code was assigned an explanation quality score.
Males performed somewhat better than females and showed higher confidence gains; however, model gender did not affect students' test performance, self-efficacy and perceived competence gains, effort investment, learning enjoyment, or perceived explanation quality.
