As policymakers and many teachers' groups push hard for merit pay, here-s some evidence from Florida that has us a bit befuddled. As part of Gov. Jeb Bush's 1999 A-Plus Plan, Florida has an optional program that rewards teachers with a bonus for exceptional merit. The bonus--equivalent to 5% of their annual pay--can be earned if teachers first apply for the program and are able to prove they are doing outstanding work in the classroom. This burden of proof is met in different ways in different districts, with some relying on student test scores as evidence, others on videotaped lessons, and yet others relying on National Board Certification and a master's degree. But the program is having trouble with low levels of participation. In Pasco County, for instance, only 4 teachers have signed up out of 3,600. It's still unclear if this level of non-participation is due to a lack of teacher awareness, insufficient financial incentives, or some other reason we can t think of.