Center on Reinventing Public Education:

School districts can take steps to level out salary inequities caused by maldistributions of teachers, according to researchers at the University of Washington.
It is a well-known fact that within districts, higher-paid teachers with more experience congregate in the more affluent schools, while poorer schools have less-experienced, lower-paid teachers.
If, as has been proposed, the federal Title I program closes a loophole in its “comparability” provision, districts would have no choice but to address the problem.
According to Marguerite Roza and Sarah Yatsko at the Center on Reinventing Public Education, districts have four “salary reallocation” options that can erase the imbalance and work to close the spending gap, without reassigning the more experienced teachers.