Teacher-Pay Incentives Popular But Unproven

The idea, in various forms, has become a popular refrain among politicians.

“I ask you to support my proposal to offer more-competitive salaries to teachers across the state,” Louisiana Gov. Kathleen Babineaux Blanco, a Democrat, implored lawmakers in March.

“Combat pay” is the term Republican Gov. Arnold Schwarzenegger gave his plan to attract well-qualified teachers to California’s toughest schools. While that phrase offended some educators, and the plan was eventually dropped last year, his meaning was clear: Reward teachers with bonuses or other financial advantages if they agree to teach in schools that other...