An Old Adage Revisited

“Those who can do. Those who can’t teach.”

We have all seen this quote and observed (accurately) that it doesn’t show the great wit that many who toss it around think. Poems have been written about it; keynote speeches have been given about it. Books and articles have been written about it.

We all despise it for what it implies about those who do the work we do, but let’s take a closer look at it. Teaching, we know, requires different types of knowledge. In recent decades TPCK (Misha & Kohler, 2006) has been used to describe seven combinations of technological, pedagogical, and content knowledge teachers need.

Real-world knowledge of the content they teach is another type of knowledge that makes for the best teachers, but this seems to be largely ignored in the “what makes a good teacher” literature. We know textbooks are written to appeal to the broadest audiences; local problems and circumstances rarely make it into textbooks or standards. We know real world applications of the ideas we teach are messy and rarely behave in the way curriculum describes them. We know there are things more important when we solve pragmatic problem that are ignored in texts and standards.

All these aspects of the ides contribute to a richness that we learn through day-to-day application of them. When I was teaching computer courses, I was also managing the IT in schools, using it for my own professional activities, and researching it. I knew what comprised important technology because I used it. My colleagues who are artists, musicians, and craftspeople bring those experiences into their classroom. Writers, computer programmers, and others also have deep knowledge that affect how they interact with students.

I often have opportunity to talk with folks who straddle the academic and professional worlds; sometimes those folks are adjunct faculty instructors, sometimes teachers who have professional lives outside of school. Sometimes teaching came first, sometimes work came first, sometimes they were coincident. These folks describe how their work improves their teaching and their teaching improves their work.

What is clear to me is the real world content knowledge they have  makes them better teachers with a longer view of learning and a broader view of knowledge than we see in traditional schooling.


Mishra, P., & Koehler, M.J. (2006). Technological pedagogical content knowledge: A framework for integrating technology in teacher knowledge. Teachers College Record, 108(6), 1017-1054.