Matter of Subject Matter, The

School Science and Mathematics, Dec 2003 by Lederman, Norman G, Flick, Lawrence B

Few would argue with the position that teachers ought to know their subject matter to teach it effectively. Indeed, "ought" is not strong enough. Teachers must know what they are trying to teach. Of course, students often learn the unintended, and what is unintended is not necessarily incorrect or undesirable. However, if we continue to hold the view that teaching is a purposeful act, it seems clear that teachers must have adequate understanding of the subject matter they are trying to teach.

Over the years, many have misinterpreted this position to mean that subject matter knowledge is all that is important and that there is virtually no knowledge base, or a very small and easily learned knowledge base, related to pedagogy. So before embarking on this discussion of the importance of subject matter knowledge, let it be clear that we do value the importance of knowledge of students, pedagogy, curriculum, schools, etc., and do not take the position that individuals with in-depth subject matter have all they need to be effective teachers.

We often see, read, or hear the phrase "adequate" subject matter knowledge, or in recent years, "in-depth" knowledge of subject matter. Whichever phrase is used, there is unanimous support, but rarely is there any concrete discussion of what "adequate" or "in-depth" mean. For most of the 20th century, studies on effective teaching focused on measures of subject matter, such as grade point average, courses taken, or degrees earned. It was an intuitive idea that a college degree in a particular discipline represents some degree of competence in subject matter, and the higher the degree the more competence one was believed to have. This belief has not disappeared, but the research on teaching has never supported in any close to definitive way that teachers with higher degrees were better teachers.

Even when our professional communities in mathematics and science education have focused solely on subject matter with little reference to teaching, many have voiced their doubts about how well individuals with undergraduate and graduate degrees really understand the subject matter. Just as an example, we have known more than one graduate student in biology who is unable to explain why whales (lung breathers) suffocate to death when beached. Or what about the graduate students who say that water does not expand when heated because "water is water"? Or students who say that water behaves differently than ice because ice is not water? And, of course, there is the much publicized problem of mathematics students who can't explain why a number cannot be divided by zero. We are sure you have your own personal favorites.

The grade point average as a measure of knowledge yielded little more success than a college degree. After all, both grade point average and degree could really be functions of the standards at various universities. We all, however, continue to be amazed by the Private Universe tapes. The trend, unfortunately, of the somewhat less than desirable relationship between teaching ability and subject matter knowledge (when measured by degree or GPA) is fairly consistent across universities. One could say that the specific courses taken would be a better measure of one's knowledge, but this has not yielded much more success other than some recent reports looking at the match between mathematics courses taken and mathematics courses taught.

In the 1980s, Shulman's construct of pedagogical content knowledge reinvigorated educators' focus on the importance of subject matter knowledge in teacher education. However, rather than focusing on measures of the past, there was much talk about subject matter knowledge structures. By definition, a knowledge structure is the "elements of memory and how the elements are organized." This talk of knowledge structures is steeped within cognitive psychology, and it gave educators another chance to revisit their intuitive idea that subject matter knowledge is critical to effective teaching. Much work was done from the 1980s to the present that relates knowledge structures to teaching practice, in general, and effective teaching practice, in particular. Knowledge structures during this period of time were measured in a variety of ways other than the formerly prized academic degree, grade point average, or courses taken. Teachers were asked to complete concept maps, card sorts, semantic networks, and similar tasks as measures of "in-depth" subject matter knowledge. Using such measures gave rise to numerous debates about the validity of scoring rubrics for such assessment approaches. For example, is it valid to use the number of connections in a concept map as a measure of a person's knowledge?

More importantly, none of these assessment approaches led to a documentation of the relationship we all KNEW existed. The relationship between knowledge structures and classroom practice was quite variable with no direct relationship documented. More importantly, the systematic study of the relationship between knowledge structures, classroom practice, and student achievement was never pursued. Even if one believes that knowledge structures give rise to differences in classroom practice, it is not clear that these differences in classroom practice impact student achievement. We remain stymied in our attempts to document what we all intuitively KNOW.