Difference between years | Prep materials# | Median | Interquartile range | Mann-Whitney U | Cohen’s d |
---|---|---|---|---|---|
Δ Difficulty z-score | Changes made No change | 0.15 0.11 | 0.08 – 0.27 0.06 – 0.19 | p < .01 | 1.1 |
Δ Familiarity z-score | Changes made No change | 0.09 0.07 | 0.04 – 0.14 0.07 – 0.12 | ||
Δ Time spent z-score | Changes made No change | 0.28 0.09 | 0.11 – 0.55 0.04 – 0.18 | p < .0001 | 1.7 |
Δ Percent score z-score | Changes made No change | 0.12 0.08 | 0.07 – 0.28 0.04 – 0.14 | p < .001 | 1.1 |
Δ Efficiency metric Ec* (score vs. difficulty) | Changes made No change | 0.19 0.10 | 0.08 – 0.34 0.04 – 0.15 | p < .0001 | 1.4 |
Δ Efficiency metric Et* (score vs. time spent) | Changes made No change | 0.27 0.08 | 0.10 – 0.45 0.03 – 0.15 | p < .0001 | 2.1 |
#N = 142 no changes N = 51 changes made 28 sessions were changed in year 2 (out of 97) and 23 in year 3 (out of 96, one session was replaced with a new topic). 97 (Y2-Y1) + 96 (Y3-Y2) = 193 total, 51 changed, 142 no change *E is calculated as (y – x)/√2. If E > 0 materials were considered efficient for learning, if < 0 they were considered less efficient for learning (Paas 2003). |