Our current empirical results, based on our factor
analyses, suggest it is likely that content knowledge for
teaching is multidimensional (Hill et al., 2004; Schilling,
in press). Whether these categories, as we propose them
here, are the right ones is not most important. Likely they
are not. Our current categories will continue to need
refinement and revision. We next highlight three specific
problems of our work to date.
The first problem grows from a strength of the work:
Our theory is framed in relation to practice. Although
this orientation is intended to increase the likelihood that
the knowledge identified is relevant to practice, it also
brings in some of the natural messiness and variability of
teaching and learning. As we ask about the situations that
arise in teaching that require teachers to use mathematics,
we find that some situations can be managed using
different kinds of knowledge. Consider the example of
analyzing a student error. A teacher might figure out
what went wrong by analyzing the error mathematically.
What steps were taken? What assumptions made? But
another teacher might figure it out because she has seen
students do this before with this particular type of problem.
The first teacher is using specialized content knowledge,
whereas the second is using knowledge of content
and students.
Two additional problems emerge from the first.
Despite our expressed intention to focus on knowledge
use, our categories may seem static. Ultimately, we are
interested in how teachers reason about and deploy mathematical
ideas in their work. We are interested in skills,
habits, sensibilities, and judgments as well as knowledge.
We want to understand the mathematical reasoning that
underlies the decisions and moves made in teaching. The
questions we pose in our measures of mathematical
knowledge for teaching are designed to situate knowledge
in the context of its use, but how such knowledge is
actually used and what features of pedagogical thinking
shape its use remain tacit and unexamined. How to capture
the common and specialized aspects of teacher thinking,
as well as how different categories of knowledge
come into play in the course of teaching, needs to be
addressed more effectively in this work.