Nonetheless, a number of small-scale studies have identified positive impacts of interactive teaching styles on student learning. As a consequence, prominent organizations such as the National Research Council and the National Council of Teachers of Mathematics, since at least 1980, have called for teachers to engage students in constructing their own new knowledge through more hands-on learning and group work. By the mid-1990s, in a study for the National Institute for Science Education, Iris Weiss could identify “some encouraging signs. The majority of elementary, middle, and high school science and mathematics classes worked in small groups at least once a week, and roughly one in four classes did so every day. Moreover, the use of hands-on activities had increased since the mid-1980s.” Even so, more than a decade later, traditional lecture and textbook methodologies continue to be a significant component of science and mathematics instruction in U.S. middle schools. A rigorous, large-scale study has yet to resolve a question that has divided pedagogical thinking for generations.