Two out of every five teenagers in Northern Ireland leave school without the basic reading and writing skills, it was revealed today.
An audit office report into literacy and numeracy levels said unacceptably large numbers of pupils were not making the grade.
Kieran Donnelly, Comptroller and Auditor General said more must be done to tackle the growing problem of educational underachievement.
He said: "Regardless of how well the majority of pupils perform, it is also clear from our findings that unacceptably large numbers of pupils are failing to achieve even minimal levels in literacy and numeracy.
"It is vital that our education system does all it can to address underachievement in order to improve the life chances of our young people and to ensure that our economy is well equipped to compete in an increasingly global market place."
Audit Office officials visited 10 primary and 10 post-primary schools as part of their examination during the 2010/11 term.
They found that, as students progressed through the system, the numbers reaching the expected standard in maths and English declined.
At the end of primary school more than one in six students (3,876) did not meet the required minimum standards.
By aged 14 (key stage 3) that had slipped to one in five.
By GCSE level, aged 16, two out of five pupils (9,000) failed to achieve the standards deemed necessary to progress to sixth-form studies, further education or step on to the employment ladder.
The report found a correlation between educational under attainment and low family income.
By the age of three, poor children were one year behind richer students in terms of communication and in some disadvantaged areas up to 50% of children
started school without the essential skills.
Pupils entitled to free school meals had a substantially lower pass rate than those not entitled and were only half as likely to achieve five GCSE grades A* to C.
The auditor said the gap between rich and poor had widened over the past six years with only 31.7 per cent of those receiving free school dinners reaching the expected level at GCSE compared to 65.1 per cent of those who did not receive free meals.
Recommendations from the report note that considerable work must be done to improve classroom practise.
The auditor said it was important for teachers to show proficiency in literacy and numeracy teaching skills, called for effective school leadership and noted that families also had a role to play.
He said: "If the Department is to tackle the stubborn tale of underachievement in our schools it may need to consider the evidence of new and alternative approaches."
The schools were selected on the basis of high achievement in 2009/10 or because of recent improvements in literacy and numeracy performance in challenging circumstances - typically with high free school meal entitlement and/or non-selective post-primary schools.
Previous research from the Audit Office on adult literacy in 2009 found that people with poor literacy and numeracy were more likely to be unemployed, suffer from ill-health or depression and be dependent on state benefits.
SDLP East Derry MLA John Dallat said he was exasperated that the progress was moving at a snail's pace.
He said: "Raising literacy and numeracy levels must be a top priority and with convincing evidence showing that literacy and numeracy difficulties demand early intervention. To address these critical gaps successful schools have shown beyond doubt that despite challenging circumstances obstacles to improve pupil and school performances can be overcome very successfully. It is not acceptable that we still have so many schools failing to address these literacy and numeracy problems.
"This report once again clearly states that applying these will help speed up improvements in literacy and numeracy in Northern Ireland and will have a positive effect on the confidence of our children and their ability to deal with every-day tasks as well as their lifelong learning and health."
PA