“Those who can, do. Those who can’t, teach.” (Attributed to H.L. Mencken)
What this is meant to illustrate is that those who have top-notch skill in a field, make their money actually doing work in that field, while those without enough skill to actually do the thing, will end up teaching (at best). Of course, those who teach hate this quote.
But there’s a point in it that’s of interest beyond the immediate meaning. It’s that, if you can do the thing, you could teach it. It’s been said that anyone with a real understanding of a technical subject, can communicate it to others, clearly, even if the students don’t have the vocabulary of the subject.
For example, I’ve experienced two people with different levels of understanding, who were both trying to explain how air conditioners work. One, who knew how to install and repair air conditioners but didn’t know the theory behind them, confused the audience with detailed descriptions of “compressors” and “Freon pumps” and so on. The second, who actually understood the whole process, asked the audience, “Have you ever used one of those cans of compressed air to blow dust off of your keyboard?” Everyone said they had. “You know how the can gets really cold?” “Yeah. Yep. Experienced that.” “Air conditioning works like that. When gasses get compressed, and then expand suddenly, they cool down, just like that dusting can.” Everyone understood.
So, if you want to test your own understanding of a subject, explain it to someone who isn’t already an expert. Once you figure out how to do that, you’ll have proved how well you yourself understand it.
Years ago, I discovered online SQL forums. I found people asking questions. Some of those questions, but only a very small number, I could answer. So I did. Other questions, I could understand what was being asked, and could almost answer it. So I researched the subject till I could answer it, and then did.
Some of my answers were challenged by others. Those challenges forced me to either clarify or defend my answer, or to correct my answer when (more often than I like to admit) my original answer had been factually just plain wrong.
I learned to build tests and to try to break them, so when I gave an answer it was already tested and I knew it would work before I suggested it. This is the senior echelon, beyond teaching and into doing, and experience in it is critical to advancing any skill.
The more questions I tried to answer, the more I learned. I found answers to questions I would never have thought of asking. And, in many cases, those questions were ones I should have been asking, but didn’t realize it. So the answers helped me as much or more than the person with the original question.
And the challenges to my answers! Awesome! I had to eat some crow, and I had to unplug my ego from the discussions, but I made that easy on myself. In doing so, I unlearned a lot of things that were wrong, learned a lot of new things, and improved my own skill.
Even when my original answer had been correct, the challenges exposed weaknesses in the answer, and I learned how to communicate my answers in such a way that they prevented the challenges from having to be posted.
Most importantly, by this process, I found a number of my own blind spots. We can never see our own blind spots, unless someone else points out, directly or indirectly, what’s in them. (That’s what makes them blind spots, after all – we can’t see what’s in them.) By reading questions I never would have asked, or reading answers by others, or by being challenged on my own answers, my blind spots were exposed.
Later, I added presenting to a PASS group to my “learning by teaching” activities.
These days, I do a monthly lunch-and-learn for the software development department at my employer. Organizing the material so that I can communicate it clearly in that kind of time-limited format, really forces me to make sure it’ll be clear and will educate rapidly.
All of these ideas and anything similar, can really help you to advance your own skill. It’s also very, very enjoyable, all by itself. If you haven’t tried it, do.