"The research was carried out on three groups of students in Israel from sixth grade through the end of high school. The students were given two exams, the first graded by objective scorers who did not know their names and the second by instructors who did know them. In math, the girls outscored the boys in the test that was scored anonymously, but when graded by teachers who were familiar with their names, the boys outscored the girls. The effect was not the same for tests in non-math or science-related subjects.
The researchers concluded that, in math and science, the teachers overestimated the boys' skills and underestimated the girls' abilities, and that this had long-term implications for students' attitudes toward these subjects.
"When the same students reached junior high and high school, we examined their performances in matriculation exams ('Bagrut' in Hebrew)," said Dr. Sand. "The boys who had been encouraged when they were younger performed significantly better than their female counterparts, though the latter had objectively scored higher at a younger age."
The researchers also monitored the advanced math and science courses that students chose to take in high school, concluding that the girls who had been discouraged by their elementary school teachers were much less likely than the boys to opt for advanced courses."
www.sciencedaily.com/releases/2015/02/150226110454.htm