A study like this really needs three groups, not two: Not only a traditional section and a flipped section in which essentially the same things take place but in a different order, but

1. A traditional section (control)
2. A “traditional flipped” section (reverse the contexts but otherwise keep it lecture + discussion)
3. An “active flipped” section where the learning activities that take place in the individual space are more active and exploratory, and not just watching video lectures; and then the group space is also active to apply the knowledge or refine the questions that emerged in the individual space.

Something like that would help distinguish (1) whether flipped environments just by their very nature have positive effects over traditional sections, which in this case there were none; and also (2) whether certain kinds of flipped environments give bigger improvements than just video lecture + class discussion.

This highlights why we need better definitions of flipped learning — a lot of people are using “video lectures at home and active work in class” as the definition and as this study points out, this may not lead to any improvements under common metrics, but that’s kind of a lack of imagination more than anything. Flipped learning can be a lot more than this, and it should be.

Also, it was a big mistake not to give students ways to communicate with the instructors and each other — that communication, when present, not only helps students’ affective responses to the class but also helps them get a better cognitive handle on the material and will help their grades. Part of the improvements you get from flipped learning on the quantitative side come directly out of that communication process — it’s not just an add-on.