  This study uses social network analysis and the Classroom Observation
Protocol for Undergraduate STEM (COPUS) to characterize six research-based
introductory physics curricula. Peer Instruction, Modeling Instruction, ISLE,
SCALE-UP, Context-Rich Problems, and Tutorials in Introductory Physics were
investigated. Students in each curriculum were given a survey at the beginning
and end of term, asking them to self-identify peers with whom they had
meaningful interactions in class. Every curriculum showed an increase in the
average number of student connections from the beginning of term to the end of
term, with the largest increase occurring in Modeling Instruction, SCALE-UP,
and Context-Rich Problems. Modeling Instruction was the only curriculum with a
drastic change in how tightly connected the student network was. Transitivity
increased for all curricula except Peer Instruction. We also spent one week per
research site in the middle of the term observing courses using COPUS. From
these observations, the student COPUS profiles look nearly the same for
Tutorials, ISLE recitations, and Context-Rich Problems discussion sections.
This is likely due to the large resolution of activities that can be coded as
"other group activity", suggesting the need for a more detailed observation
instrument.
