  We report on a multi-year study of student attitudes measured with the
Colorado Learning Attitudes about Science Survey (CLASS) in calculus-based
introductory physics taught with the Modeling Instruction curriculum. We find
that five of six instructors and eight of nine sections using Modeling
Instruction showed significantly improved attitudes from pre to post-course.
Cohen's d effect sizes range from 0.08 - 0.95 for individual instructors. The
average effect was d = 0.45, with a 95% confidence interval of (0.26 - 0.64).
These results build on previously published results showing positive shifts in
attitudes from Modeling Instruction classes. We interpret these data in light
of other published positive attitudinal shifts and explore mechanistic
explanations for similarities and differences with other published positive
shifts.
