As part of a larger comparison of the school-to-work transition in Switzerland and Great Britain, instruction in mathematics, science, and practical subjects (industrial arts and home economics) in the two countries was compared by two methods: site visits to English and Swiss schools by teams of English teachers and inspectors and analyses of the performance of samples of English and Swiss students on the International Assessment of Educational Progress (IAEP). Of the English and Swiss pupils selected on a representative basis, 47% and 80% participated, respectively. The Swiss students scored significantly higher on the IAEP than the British students did. Although some English students met standards as high as those observed in Switzerland, Swiss students generally appeared to be 1-2 years ahead of their English counterparts. The observed differences between English and Swiss students' levels of achievement were attributed partly to differences in the teaching styles and syllabus content observed in the two countries and partly to the excellence of Swiss primary school teachers. Emphasis on pupils' active involvement in the learning process was greater in Switzerland. (Contains 78 footnotes. Appended is information on a Swiss experiment in comprehensive schooling.) (MN)