More high school students are taking college-preparatory courses now than three years ago, according to a study by a Stanford University education professor. Michael W. Kirst has told the state Board of Education that California high schools are offering 20% more mathematics and social science classes and 12% more foreign language courses and that enrollments in those classes are rising, primarily because of “aroused public opinion” about the quality of education. Kirst said the high schools have made room for the harder courses by dropping electives such as home economics, industrial arts, anthropology and social psychology. He also said that high schools are making writing, which had been an elective in many schools, part of the core English curriculum. “It is especially noteworthy that schools with large minority populations or whose students are from low socioeconomic backgrounds, also show impressive increases” in academics, Kirst said.