More than 60 per cent of the 500 16 to 25-year-olds polled by Washington DC research firm Civic Enterprises for the Bill and Melinda Gates Foundation - the largest private donor to US schools - had average grades of C or higher, before dropping out.

Nearly half cited boredom as a chief reason for leaving school, with nearly seven out of 10 saying they did not feel motivated. Two-thirds said they would have applied themselves more had they been pushed harder.

John Bridgeland, former domestic policy adviser to President Bush and co-author of the report, released earlier this month, said the findings held out hope. “These kids are capable. They want teachers to have higher expectations, give them greater challenges and more inspiring work.”

Mr Bridgeland said the study highlighted the need to link classroom learning to students’ career aspirations.

Jay Smink of the National Drop-out Prevention Center at South Carolina’s Clemson university said it showed how efforts to reduce numbers dropping out by offering struggling students extra instruction were only part of the solution.

“Most people think education can solve it. That’s where most schools go wrong. Kids often drop out for academic reasons, but there are many others reasons.”

One-third of those polled cited falling behind academically as a major factor which led them to drop out of school.

One in three students fails to complete their schooling. The problem has persistently been identified as one of the most pressing facing schools in the US, especially amid growing wisdom that education up to at least 18 is the minimum preparation students need for today’s workforce.

Six US states are considering raising the school-leaving age from 16 to 18, said Mr Bridgeland.