We studied student learning in the MOOC “Mechanics ReView”, run on the edX. org open source platform as 8. MReV. We administered 13 conceptual questions both before and after the instructional period, analyzing the results using standard techniques for pre-post testing. Our students had a normalized gain slightly higher than typical values for a traditional course but lower than typical values for courses using interactive engagement pedagogy. All questions in the MOOC, including the pre-post test questions were analyzed using Item Response Theory (IRT). Both the normalized gain and the IRT results showed that initially lowskill cohorts learned as much as all cohorts with higher initial skills. We were able to compare MIT freshmen taking an oncampus course with the 8. MReV MOOC students because many common problems were administered to both groups. The freshmen were considerably less skillful than the 8. MReV students and showed no signs of closing the gap with the more experienced 8. MRev students while covering topics in common with the MOOC.