What kind of instructional models produce better conceptual gains?

At UMCP we are testing a change in our traditional instruction.
- The TA problem-solving recitation is replaced by a group-learning concept building activity.
- “Tutorials in Introductory Physics” (McDermott and the UWPEG) helps the students to learn qualitative reasoning with research-based worksheets.
About half of the lecture classes have recitations, half tutorials. Students in the first (mechanics) semester were tested with pre- and post-FCI.