Has Teacher Quality Declined?

As New Jerseyans await the State Legislature’s promised debate on reforming teacher tenure, there’s two pieces today that address the impact of lifelong job security and union power on classroom effectiveness.

First, Lee E. Ohanian, a Professor of Economics at UCLA, explains how teacher unions affect the quality of teachers in American schools “by protecting teachers who do not perform well.” In "America's Public Sector Dilemma" he cites research by Caroline Hoxby, a labor economist at Stanford, that shows that, in spite of higher spending per pupil since the 1960’s, “teacher unions are responsible for increasing the resources devoted to public education by using their market power in bargaining with school districts, and that, despite higher spending, unions depress the quality of education by reducing the productivity of teaching.”

Ohanian continues,
Caroline Hoxby and Andrew Leigh find that the share of teachers who are among the top aptitude individuals, as measured by SAT scores, has declined over time from about 5 percent of teachers in 1963 to only 1 percent in 2000, and that much of this decline is due to the fact that teacher unions, like most other unions, compress compensation, which means that the spread in compensation between the highest quality and lowest quality teachers is reduced. And it is not only the very top aptitude individuals that are entering teaching at a lower rate. Wage compression benefits lower ability teachers, but reduces compensation of the best teachers, and this decline in compensation at the top end leads to fewer top aptitude individuals pursuing a teaching career.
In a related article today, Matthew Di Carlo in The Shanker Blog notes that the “cognitive ability” among female students who choose teaching as a career has declined over time:
An important 2004 longitudinal analysis of the trend in teachers’ cognitive ability (as measured by math/reading tests) suggests that the proportion of female students who both chose teaching and scored in the top ten percent on these tests was around 15-17 percent in the late 1950s, compared with roughly 7-8 percent in the early 1990s (also see here). There were similar, though less pronounced, patterns among female students scoring in the top 70-90 percent. This suggests, in other words, that the highest-achieving (at least as measured by these aptitude tests) young women are more likely to choose other professions than they used to be.
Di Carlo also notes that part of the decline of teacher cognitive ability, at least among females, is due to the expanding opportunities for women in the work force. (The choices aren’t just social workers, teachers, or nurses anymore.) Ohanian, however, attributes much of the decline to the lack of competition for higher salaries, since compensation for teachers is frozen into salary guides that disregard effectiveness in the classroom. He points out the much-publicized case of Megan Sampson, “a public school teacher in Milwaukee, Wisconsin, [who] was laid off because of lack of seniority, even though she received Wisconsin’s outstanding first-year teacher award.”

Di Carlo is no anti-unionist. His blog is funded by AFT and he describes his mission (on the blog's homepage) as advocating for “teacher unions as advocates for quality;" understandably, he posits no link between the decline in teacher quality and the lack of differentiation between great teachers and lousy ones. But he and Ohanian (who hails not only from UCLA but also from the Conservative American Enterprise Institute) dovetail in their agreement on national problems in attracting smart and ambitious candidates to the teaching profession.

It’s not too hard a stretch to see that the unions’ trade-offs – sacrificing competitive salaries for job security and back-loaded compensation systems like pensions – are less appealing to smart young people, particularly (according to DiCarlo) women. Whom do we serve by maintaining the anachronistic system of rewarding fidelity instead of quality? We know it's not the kids. Apparently it's not our new promising teachers either.