Last week, during a break from my graduate school education policy classes, I had the opportunity to visit my old school and spend some time with my students from the last two years of my teaching. It was a great day. The excitement and joy of the kids were truly overwhelming.

At the end of the day one of my students, a heartbreakingly adorable girl whose thick Spanish accent is slowly lightening up, told me that one of her former classmates is “mean now.” We talked briefly about this before we had to go our separate ways. Although it was a small moment in the course of the day, it sticks out in my mind now as a reminder of the profoundly multifaceted world of children.

It stands out now in stark contrast to the relatively simple, safe environment of my college classrooms. This week in my class on teacher quality we simulated a panel on teacher pay structure for the Rochester City School District. We grappled with the intricacies of teacher pay and the concerns of different stakeholders as we weighed different benefits and costs. And yet the exercise felt incredibly uncomplicated compared to the ecosystem I used to share with 25-30 children. This disconnect is one I am constantly aware of and working to bridge as I prepare for my transition from the theory of education reform to its practice.

Earlier in the day during that same visit to P.S. 310 I received a note from one of my old students. It was a short thank-you note, but I was deeply moved by the innocence and sincerity of its tone. For some reason as I read the note my mind flashed to a phrase from a Hebrew psalm, “If I forget you, O Jerusalem, let my right hand forget its skill!” Those words, “If I forget you,” were unshakable. Just as Jerusalem is at the heart of the Jewish faith, so must the classroom and the kids within it remain central to my work in education. If I forget that, I need to find a new line of work.

Solving the big problems of education is certainly difficult. I am grateful to have the time and space away from teaching this year to study, think and discuss the questions of how to build a better system. At the same time, I am consistently thinking about the distance between my work at Harvard and the work I did in the classroom. The classroom is where the solving of the big problems will eventually take place, and as my short visit reminded me, there are countless variables that are often hard to remember from afar.

In several of my courses we have discussed the concept of the instructional core. Essentially it is the idea that at the center of the framework for all successful education systems is a successful relationship between teachers and students. While the ideas for education reform might sometimes originate in universities or district offices, this idea can’t be ignored. The teacher-student interaction is remarkably complex, but it is the nexus of educational transformation. It’s vital education leaders never forget that.