Teachers don't respond to incentives

In a three-year study, some Nashville math teachers were offered bonuses of up to $15,000 based on their students' scores on standardized exams:

With respect to test scores in mathematics, we find no significant difference overall between students whose teachers were assigned to the treatment group and those whose teachers were assigned to the control group.
...
To conclude, there is little evidence that POINT incentives induced teachers to make substantial changes to their instructional practices or their level of effort.

The study found neither better test scores nor higher effort levels associated with paying fairly sizable bonuses.