Ask a parent, politician, or school board member to describe the ideal qualifications of a math teacher, and most would probably rank having a college major in that subject high on the list.
Yet when it comes to improving student learning in elementary and middle school, research shows that the value of that academic credential is limited—at best.
On the one hand, recent nationwide test scores show middle school students taught by a teacher with an undergraduate mathematics major scoring better, on average, in that subject than those whose teachers did not have that degree. Yet many observers view those results with caution, saying the weight of evidence does not show a connection between teachers’ having majored in math and higher student math achievement, particularly before high school...
Math teachers need to “know the subject matter well and how to teach it,” said Deborah Loewenberg Ball, a scholar who has studied math teaching extensively. “The problem is that the math major is not a good proxy for that.”
An in-depth knowledge of math is necessary, but not sufficient, for being a good math teacher. There's much more to teaching than just content knowledge.
But let's not downplay the importance of content knowledge.