interactions is the surest way to improve education in these subjects in the United States.
Many mathematics and science teachers in US schools do not have backgrounds needed to teach these subjects well (see Figure K–12-4).5 Many of these teachers at the high school level—and even more at the middle school level—do not have a college degree in the subject they are teaching (see Tables K–12-9 and K–12-10). Many lack certification to teach mathematics and science, and a subset of teachers start in the classroom without any formal training. The lack of adequate training and background is especially severe at schools serving large numbers of disadvantaged students, creating a vicious circle in which a substandard education and low achievement are intertwined (see Table K–12-11). The stresses on teachers are equally se-