This toxic combination of rigid pay and steep rewards for seniority causes average quality to decline rather than increase as teacher groups get older. Top performers often leave the field early for industries that reward their excellence. Mediocre teachers， on the other hand， are soon overcompensated by seniority pay. And because they are paid more than their skills command elsewhere， these less-capable pedagogues settle in to provide many years of ineffectual instruction.

So how can we separate the wheat from the chaff in the teaching profession？ To make American schools competitive， we must rethink seniority pay， the value of master’s degrees， and the notion that a teacher can teach everything equally well—especially math and science—without appropriate preparation in the subject.

Our current education system is unlikely to accomplish this dramatic rethinking. Imagine， for a moment， that American cars had been free in recent decades， while Toyotas and Hondas sold at full price. We‘d probably be driving Falcons and Corvairs today. Free public education suffers from a lack of competition in just this way. So while industries from aerospace to drugs have transformed themselves in order to compete， public schooling has stagnated.

School choice could spark the kind of reformation this industry needs by motivating administrators to hire the best and adopt new strategies to keep top teachers in the classroom. The lesson that good teachers matter should be taught， not as a theory， but as a practice.