A new study has found that national pay scales for teachers can have a damaging effect on pupils' achievement.
It argues that in areas where private sector salaries significantly outstrip teachers' wages, pupils can drop up to one GCSE grade in one subject.
The study, by researchers at Bristol University, examined teachers' pay and school performance in around 3,000 English secondary schools between 2002 and 2008.
Under the current system, teachers' pay is set centrally by the School Teachers' Review Body. As a result, there is little variation between teachers' wages in different English regions.
This means that their salaries do not fully reflect regional differences in pay in the private sector, the researchers say.
The average difference in teachers' pay in the north east and London is around 9%, the study says, but the difference in private sector wages between these two regions is more than 30%.
It argues that centralised pay for teachers acts as a "pay ceiling" for those working in areas where private sector wages are high - usually affluent areas.
The study concludes that a 10% increase in the average private sector wage paid in a region leads to the loss of around one GCSE point per pupil - the same as dropping one grade in one subject.