School readiness at age 4-5 could help predict unemployment and education drop-out at age 16-17, according to researchers.
The study by Lancaster University and the University of Leeds revealed that children who were behind in their development at age 4-5 were almost three times as likely not to be in education, employment, or training (NEET) at age 16-17.
There was also a large gap between the school 'ready' and 'unready' 4-5-year-olds at GCSE level.
The study in the journal BMC Public Health drew on data from more than 8,000 Bradford young people whose records are joined up as part of the 'Connected Bradford' project.
The Early Years Foundation Stage Profile is used to assess 4-5-year-olds at the start of primary school. Those who reach the threshold of a 'good level of development' are considered 'school ready'.
The research found that 11% of children who were not school ready went on to be NEET at 16-17, compared to just 4% of children who were school ready.
This early disadvantage also predicted achievement at GCSE level. Of children who were assessed as not school ready, 44% achieved GCSEs at level 2 (grade 4 or above) in English, Maths, and five subjects overall, whereas 77% of those school ready achieved these results.
Senior author Dr Amy Atkinson, from the Department of Psychology at Lancaster University said: "Data from the Early Years Foundation Stage Profile is readily available for millions of children and young people in England. This information could, and should, be used to identify pupils at increased risk of becoming NEET."
Lead author Dr Matthew Warburton from the University of Leeds said: "These findings tell us that there are clear, early indicators for children and young people being at risk of disadvantage in late adolescence. As schools routinely collect this data, the research could be used to kickstart early intervention in schools based on primary school readiness."
The research team, which included the Bradford Institute for Health Research, say this shows a clear need for early intervention by schools to reduce disadvantage in later life.
This echoes the message from a series of N8 Child of the North and Centre for Young Lives reports on the need to put children and young people first.
The researchers point out that data availability meant that NEET could only be assessed at 16-17 years of age, with further work needed to assess this trajectory over a longer timescale.
