Project-based learning isn’t a ‘trend’ any more than mobile devices are a trend.
Mobile devices–smartphones, for example–simply provide a (physical) framework to host hardware (e.g., iris scanners, cameras, etc.) and software technology (e.g., an operating system, apps, etc.) These devices in and of themselves aren’t as much of a ‘trend’ as are the things that they enable. Project-based learning is kind of like that.
As the name implies, project-based learning is simply learning through projects. What is being learned and how that learning is being measured isn’t strictly dictated by the project and any products or artifacts within that project. Rather, the reverse should be true: the desired learning objectives should help dictate the products and artifacts within the project.
For example, instead of wanting students to plan a garden as the core of the project, then deciding which learning objectives and academic standards fit that idea, planning backward–looking first at the learning objectives and academic standards, then brainstorm project ideas and components of that project (audience, purpose, duration, etc.) This can be useful in making sure that in the course of completing the project, they are actually learning what you want them to learn. That is, you can help align the work of the project with the desired learning outcomes and objectives.
(To further complicate matters, there are also different types of project-based learning.)
For whatever reason, PBL is widely misunderstood—which is why I was happy to see the following graphic from John Spencer, who allowed us to share it with you along with our other PBL resources. The graphic clarifies 13 potential outcomes of well-designed project-based learning. Obviously, not all are true every time for every student in every project in the same way that not every app on a smartphone works well, nor does every bit of hardware function the way it’s intended to.
It’s all a matter of design and quality.