The consensus among Edupundits is that teacher quality is the most important variable in student academic achievement.
I argue that the most important variable in student academic achievement is student academic work.
Edupundits have chosen very complex subject matter for their investigations and reports. They study and write about dropouts, vouchers, textbooks, teacher selection and training, school governance, budgets, curricula in all subjects, union contracts, school management issues, and many many more.
Meanwhile, practically all of them fail to give any attention to the basic purpose of schools, which is to have students do academic work. Almost none of them seems inclined to look past the teacher to see if the students are, for instance, reading any nonfiction books or writing any term papers.
Of course all of the things they do pay attention to are vitally important, but without student academic work they mean very little. Now, I realize there are state standards in math and reading, and some states test for writing after a fashion, but no state standards ask if students have read a history book while they were in school or written a substantial research paper, and neither do the SAT, ACT, or NAEP tests.