Parents who offer their children cash incentives for good GCSE results should stop doing so, research shows.

An experiment undertaken by Bristol University and the University of Chicago has found that the promise of a financial reward did not make GCSE students any more likely to do well in their exams or to work harder to achieve better grades.

The news will come as a surprise for many British parents who 'bribe' their children with huge cash sums and expensive rewards, including cars and iPhones, to encourage them to work harder in their GCSEs.

Discussions on Mumsnet show parents voicing their horror at friends, who give their children £100 or more for every A grade – meaning they could be paying out more than £1,000 to their 16-year-old come results day.

The experiment

More than 10,000 teenagers in 63 schools studying for GCSEs in English, maths and science took part in the research project. Each was given £80 at the start of each half term and told their money would be deducted for not attending class, bad behaviour, and for failing to achieve their classwork and homework goals.

The students involved overwhelmingly failed to meet targets set out for their school work and were deducted heavily. Researchers believe the money was no incentive when it came to completing work.

The promise of money also had no impact on the students' behaviour, attendance or homework effort, researchers said.

Dr Kevan Collins, Chief Executive of the Education Endowment Foundation, which published the research said: "The use of incentives in schools is not a new idea and can appear attractive to schools and parents, who are trying to motivate their children.

"The study suggests that while incentives [such as school trips] can increase effort in the classroom, the direct impact [of financial incentives] on learning is low."