  A two-stage collaborative exam is one in which students first complete the
exam individually, and then complete the same or similar exam in collaborative
groups immediately afterward. To quantify the learning effect from the group
component of these two-stage exams in an introductory Physics course, a
randomized crossover design was used where each student participated in both
the treatment and control groups. For each of the two two-stage collaborative
group midterm exams, questions were designed to form matched near-transfer
pairs with questions on an end-of-term diagnostic which was used as a learning
test. For diagnostic test questions paired with questions from the first
midterm, which took place six to seven weeks before the diagnostic test, an
analysis using a mixed-effects logistic regression found no significant
differences in diagnostic-test performance between the control and treatment
group. For diagnostic test questions paired with questions from the second
midterm, which took place one to two weeks prior to the diagnostic test, the
treatment group performed significantly higher on the diagnostic-test than
control.
