State-school pupils in affluent areas may perform poorly in their GCSEs as their teachers are more likely to feel under-paid and move to the private sector, it has been claimed.
A new study has found national pay scales for teachers can have a damaging effect on pupils' achievement as state schools in wealthy areas struggle to retain the best teachers.
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 (STRB).
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.
Schools in these areas may struggle to recruit and retain good teachers, and high-quality teachers could decide to leave the profession or move to areas where their salary will stretch further.
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.
Report author Professor Carol Propper said: "Where the gap between the private sector and what teachers are paid is biggest, teachers in these areas will feel that they are paid less than they ought to be."
She added: "The effect comes from the comparison between fixed teacher wages and the variable outside private wage."
Private sector wages help to set, and reflect, things like house prices, Prof Propper said.
"Where teachers are most likely to feel under-paid is where pupils are most likely to do less well."
Teachers' pay has come under the spotlight in recent months.
The government is considering proposals which would allow schools to set their own staff salaries.
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