Dale concluded that coeducation improves the progress of boys' education while it has essentially no effect on girls' education. Marsh notes, however, that Steedman's study was based on important corrections for pre-existing factors. Other studies, Marsh explains, have tended to side with the conclusions of Coleman, who proposed the negative effects of coeducation. The bulk of Marsh's study focused on the role of school typ and sex differences in the in the various results found in both learning environments. Marsh explains that past studies tend to show that girls achieve in verbal areas and boys in math and physical sciences.
Studies also show other stereotypical differences in the sexes.
These differences, when applied by Marsh to the coeducational or single-sex environments produce varying results. He related these questions to results from Lee and Byrk studies which sampled a similar pool of students from the sophomore to the senior years. He concludes that his findings about school type effects are valid only if corrections are made for the pre-existing background variables. While many results from his study indicate advantages for single-sex schooled boys, they cannot be interpreted as school type, since background variables could account for those advantages. Why it Works at the Middle School Level.