Bribing children from poor homes with cash rewards to attend school, do their homework and read books is the most effective way to boost their results, research has found.
The lure of money is a more effective way to boost their attainment than other initiatives, according to a review of more than 165,000 research studies.
But offering money for results has little impact because children from poor backgrounds do not know what steps to take to succeed, the research says.
The conclusions, from Professor Stephen Gorard of the University of Birmingham, were presented last week at the American Educational Research Association conference in San Francisco. They draw on research in Australia, Britain and the US.
Professor Gorard recommends that schools put aside up to US$200 (#163;130) a year for poor students, a portion of which is taken away each time a student fails to meet goals on attendance and work. In the UK, the money could be aimed at students who are eligible for free school meals, but other countries have tried a tiered approach, Professor Gorard said.
His research calls into question government investment in schemes that attempt to raise student aspiration on the basis that aspiration alone will improve results. The study found that neither parental expectations of educational success nor students' own aspirations made any difference to their actual grades. "Aspiration could be an indication of success, not its cause," Professor Gorard said.
By contrast, when students were offered financial rewards for academic performance, there was a noticeable difference. Several studies, involving more than 40,000 students in total, considered the effects of educational bribery. When students from state schools in four US cities - Chicago, Dallas, New York and Washington, DC - were offered financial rewards in exchange for good test results, it did not have a significant effect.
"Interviews with the students suggest that although they may be excited about the incentives, they do not know how to improve their grades," Professor Gorard said.
But paying students for the smaller steps that led to good results had a more positive effect. When students were rewarded for attendance, good behaviour, completing their homework and wearing correct uniform, their reading and maths scores improved.
Paying students to read books led to a noticeable improvement in reading comprehension, Professor Gorard said, and offering cash rewards to children's families for engaging in educational activities also had a positive effect on results.
He said that while investment in initiatives to raise aspiration might not improve results, it could have other benefits. "Attainment is important but it is only one possible educational outcome," he said. "Others - such as future participation, well-being, preparation for citizenship, resilience and happiness - could be just as important.
"Interventions to make school more pleasant and enjoyable, so enhancing school engagement, may not (translate) into improved grades. But this is still an intrinsically good thing to do."