(cross-posted from my blog, Sunday Stopwatch)

"But when am I going to use any of this?" - every single kid in school ever.

There's an idea that project-based learning is more efficient than the traditional school curriculum. It makes sense, but so did the idea that learning styles are important, and that turned out to be false.

Here are a couple of thoughts before I delve into the research:

1. When I'm learning about something, it stands to reason that, in the long run, I'll learn more if I'm interested in the material. One way of being interested in the material is to have a specific goal in mind, the achievement of which depends on you learning the material. However, as anyone with any goal whatsoever knows, some things you want to do very much, but you really don't want to do some of the background work for them.
2. Having a specific goal (a project) will serve as a wrapper around the exact same thing you would be doing following a traditional curriculum: reading textbooks and solving quizzes. Let's say you're trying to build a robot and realize that you need to learn about classical mechanics to achieve that goal. You'll bust out the textbook, try to figure out the page which will solve your specific problem, you will fail because you have a specific situation which requires a deeper understanding of the entire field of classical mechanics, and then you'll end up doing what you would have been doing anyway: reading textbooks and doing quizzes.
3. With that being said, you do provide an answer to the question "why do I need to know this?", but it's not clear to me that knowing an application for something really makes a difference in knowledge retention. I know the application of the equations used for electrical circuits, but it doesn't mean I remember them.
4. But maybe the act of applying itself is what makes the knowledge stick in the mind. There's a relatively easy way to test this: set up three groups, two project-based, and one traditional. When one project-based group gets stuck on the project, and they obtain the knowledge needed to "unlock" progress, simply level them up without them actually applying the knowledge. So if they're e.g. building a robot arm, and they are missing some crucial insight into a particular subfield of physics, when they go and obtain that knowledge using traditional methods, just give them a working robot arm (or whatever the project is) and face them with the next challenge. The other project-based group should actually apply the knowledge - the members themselves should go and build whatever they're building. Finally, test the knowledge of the three groups and see if the act of applying knowledge had any effect on retention.

I expect that having a project-based approach serves as a minor boost to motivation, but doesn't really make a difference regarding knowledge retention.

So, what does the research say?

This systematic review says that it's inconclusive because the studies weren't done well. And this is only for small kids. I could imagine that different approaches might have different effects depending on age.

This paper describes how biomedical engineers collaborated on some projects and concludes that project-based learning works well. Direct quote: "It is felt that the projects were successful to some extent. They certainly achieved several important learning outcomes of teamwork, ability to apply theoretical principles from multiple disciplines, effective communications, creative problem solving, and awareness of the importance of globalization especially in the biomedical engineering field." It is felt that I don't have any new insight after reading the article.

This paper tries to figure out the effects of project-based learning on "on collaborative learning, disciplinary subject learning, iterative learning, and authentic learning", none of which sound like "we made both the control and experimental group take the same quiz afterwards". And looking at the methodology - it's not. They just asked a bunch of teachers some questions. I don't consider this informative.

There's "Baran, M., & Maskan, A. (2011). The effect of project-based learning on pre-service physics teachers electrostatic achievements. Cypriot Journal of Educational Sciences, 5(4), 243-257.", but I can't access that text, only the cached abstract, which speaks in favor of project-based learning. But they had only 20 people in the treatment group, and I have no idea what the methodology even was, so... this one also fails.

This review also concludes that "a causal link between PBL instruction and positive student outcomes cannot be established with certainty".

My conclusion: we just don't know for sure. I think that having a project serves as a motivator and a framework, but if you are the type of person that doesn't need to immediately know how you'll apply the thing you're learning, then it's more or less the same. For example, if you blindly trust that logarithms will be useful for something later on, then you don't actually need a project for which logarithms would prove crucial. In both cases, you'll end up doing the same thing: reading textbooks and doing practice problems.

Please let me know if you know more about this topic!