Charity the Nuffield Foundation has funded research that will analyse education-related data on 7,300 21-year-old care leavers, as well as carry out interviews.
Government statistics from 2017 showed 40 per cent of care leavers aged 19 to 21 were not in education, employment or training (Neet), compared with 13 per cent of the same age group in the general population.
Researchers from the University of Oxford's Rees Centre and the University of York plan to compare outcomes of three groups of 21-year-olds.
They are: young people who just fell short of qualifying as care leavers; young people categorised as children in need following a social services assessment or because of a disability at age 15 to 16; and children who fall into neither category.
They will interview care leavers, young people and key people in their lives including foster carers and professionals from local authorities, education and employment sectors.
They will also work with three pairs of local authorities to explore in depth different approaches to supporting care leavers' transitions from compulsory education.
Rees Centre principal investigator Eran Melkman said the research aimed to explore the paths taken both pre- and post-16 that lead care leavers to better or worse employment outcomes.
"We also want to identify factors, such as extending foster care beyond age 18, that may be associated with more resilient outcomes," said Melkman.
"Identifying these factors will assist policymakers and service providers to better support care-experienced young people into employment."
Nuffield Foundation director of education Josh Hillman added that the research could also provide insight into why there was a correlation between children in care and those in custody.
The study will run from March 2019 until August 2020.
A film about the Care Leaver Covenant, an initiative to help create opportunities for care leavers
The government has tried to address this problem by launching several initiatives to promote better outcomes for care leavers.
In February 2018 it announced extra funding to extend a virtual school heads scheme for children in care to include children who had left care up to the age of 18.
It also provided more funding to care leavers' personal advisers to ensure all care leavers were supported up to the age of 25, not just those identified as Neet.
In May 2018 the government announced care leavers choosing to take up apprenticeships would receive a £1,000 bursary payment.
While in October 2018, the government launched a Care Leaver Covenant which asked businesses to sign up and create 10,000 work placements, internships or training sessions for young care leavers.