Teachers on a performance-pay scheme have helped their pupils to achieve higher GCSE results, research suggests.
Teachers' representatives have criticised the report
A study by Bristol University said pupils of teachers on a bonus scheme scored half a grade higher in their GCSE subjects.
Teachers in England become eligible for extra payments once they have been in the profession for five years.
Teachers' representatives - who oppose the pay scheme - have cast doubt on the study's findings.
Research was carried out by Professor Simon Burgess and Professor Carol Propper, of the Centre for Market and Public Organisation.
They looked at the results of pupils of the same individual teachers before and after the introduction of performance-related pay (known as the threshold scheme) in 2000.
They analysed the results of 181 teachers at 25 schools in England, following the progress of 14-year-old pupils from their key stage 3 tests up to GCSEs.
They concluded that higher pay did achieve better grades.
The difference was more marked for lower-achieving 14-year-olds, they said.
The researchers concluded: "Comparing pupils with the same scores at key stage 3, those taught by teachers who were eligible for performance-related pay achieved on average half a GCSE point more than equivalent pupils taught by the same teachers before the scheme was introduced.
"Like workers in many other professions, the evidence is that teachers do respond to direct financial incentives tied to their performance."
Teachers who were eligible for the scheme, they said, improved the value-added of their pupils by more than those who were not.
Teachers become eligible for an annual £2,000 bonus once they have been in the profession for five years, reach certain targets and meet other criteria.
The scheme was criticised by teaching unions as divisive when it was brought in.
The National Union of Teachers said the research was not making a fair comparison.
A spokeswoman said: "It is criticising those teachers who are not yet eligible for the payments - relatively newly qualified teachers - and they are a small group compared to the whole profession".
Alan Gotch of the education, policy and research team at the Association of Teachers and Lecturers has written to Prof Burgess expressing a reservation about the findings.
"Threshold payments are not directly related to the specific examination results of any group of pupils," he said.
"The threshold is based on an overall review of performance, and is a reward for demonstrating overall a high level of competence.
"Would it not be fairer to state the results in terms of increased performance overall once their professional skills were rewarded with higher pay, rather than implying that they have responded to a specific reward related target?"