A most puzzling graph in the New York Times shows that male teachers earn 10% more than female teachers. The exception is special education where they make 3% more than men. It is puzzling because so many teachers are in collective bargaining agreements and those contracts do not distinguish between male and female. A note on the university level says that there are more tenured male professors which is why they make more.
Since teacher pay is not based on performance and only is increased by time in the profession, degrees or advanced certification it must mean that, on average, male teachers have longer time in the classroom than the average female teacher.
No real conclusion or cause to advocate – just an interesting data point.