 What are threshold concepts? According to my year, threshold concepts are particular concepts we encounter in our learning journey that are acting like a one-way portal Irreversibly changing the way we think. I like to think of it like the series of gates with the path under it, the learning journey. Each gate represents a threshold concept that you need to step through to get to the next phase of the learning. If you're not properly going through the gate, it is very difficult, if not impossible, to continue. Once you step through one of these gates, you might get the new way of seeing the world. Now if you're unable to go through the gates, continuing on this path will be very difficult and I'm pretty sure most of us at some point, if the gates are not open, will simply stop trying. There are certain characteristics usually associated with threshold concepts. They are, first, transformative. A threshold concept transforms the way we are thinking. Second characteristic is that they're irreversible, meaning that once you truly master a threshold concept, it's impossible to go back to the way you were thinking before or forget what you learned when you cross that concept. They're integrative in the sense that they create connections to other pieces of knowledge you already have. And they're bounded, meaning that often threshold concepts are creating the boundaries of a discipline. The way that you see the world after crossing a certain threshold could be particular to your discipline. Threshold concepts often are also troublesome, which means they could be difficult conceptually or conflicting with previous views and conceptions and simply be alien. There are also certain consequences that, according to literature, often will appear if a threshold concept is not mastered. One of that is remaining stuck. You simply cannot progress in your learning journey if you didn't clear the threshold properly. Another one is fragmented knowledge, meaning that you cannot link up the pieces of knowledge you accumulated. It could also result in problems learning other concepts that rely on you having mastered a certain threshold concept before continuing on your path. Often the result of not having clearly understood a threshold concept and mastering it is to resolve to mimicry or surface learning. And last but not least, repeatedly trying to master a threshold concept but not being able to do so and by that being blocked in the learning journey can cause a loss of motivation leading to disengagement and students stopping to even try at some point. My first reaction when I learned about threshold concepts was, oh yeah, we have a couple of those in our courses. It felt to me like I was actually passing through a threshold looking at why the students struggle in the courses in a complete different way and suddenly getting some more understanding why I see students insisting on using the surface approach or at some point losing their motivation. Now which characteristics does a concept need to have to be considered a threshold concept? Most of the literature does agree that a concept should be at least transformative to be considered a threshold concept and then depending on the order or the study, other of the characteristics were considered as a requirement or not.