In the English reports I've been reading recently, Ofsted inspectors simply do not accept the idea that teaching quality has to vary widely from classroom to classroom. They expect teachers to work together to achieve excellent teaching schoolwide, applying the practices common to professional learning communities. They expect head teachers to give priority to developing similarly high levels of skill throughout their staffs. They describe excellence with words like "consistently, " "constantly," "not just occasionally but for a high proportion of the time," and "not ... by chance, but by highly reflective, carefully planned and implemented strategies" (all used here).
The American idea of performance pay is to figure out which teachers deliver the best results, pay them more, and hope that that added pay works as an incentive for other teachers to improve and stronger applicants to enter the teaching field.
Implicitly, performance pay accepts big differences in teaching quality. It assumes that we cannot, directly, through focused attention and systematic leadership, equip all teachers to move students forward to high standards. It assumes that big gaps between what one teacher does and what another can accomplish are unavoidable.
The English experience, backed up by rising student performance on national and international measures, says we don't need to settle for difference like that.