Children who are home educated are four times more likely to be out of work, education or training by the age of 16 than schooled children, a Government adviser claimed this week.
Graham Badman, who is leading a Government inquiry into home education, told the Commons schools select committee that the data relating to home- educated children who become Neets - young people not in education, employment or training - was "stark".
According to evidence submitted by a sample of 47 local authorities for the review, 22 per cent of young people who were home educated and had turned 16 by August 2008 were described as being Neet, against a national percentage of 5.3.
Mr Badman, a former director of children's services in Kent, told the select committee: "If you look at the Neets data, it is stark. The percentage of home-educated children who are not in education, employment or training is higher than in the national population."
In June, Mr Badman issued a report recommending all parents wishing to educate their children at home should register with their local authority. It also said authorities should refuse registration if they believe a child to be at risk.
The review was commissioned by Schools Secretary Ed Balls to address concerns about the link in a "very small number of cases" between home education and children suffering harm.
During the select committee hearing on Monday, Mr Badman also told MPs that data submitted from 74 local authorities indicated that home-educated children are twice as likely to be known to social services as those who go to school.
According to the figures, 0.4 per cent of home-educated children were on child-protection plans against 0.2 per cent of all children.
Mr Badman said: "The children I met during this review were very accomplished, but that doesn't mean we can say that all children are safe. The data is only a sample of the population, and although that figure could go down it could equally go up."
Barry Sheerman, select committee's chair, asked schools minister Diana Johnson whether the document put too much focus on home-education "horror stories".
Ms Johnson said the UK had the most liberal approach to home education in the developed world.
She added: "A lot of the recommendations are about creating a positive relationship between local authorities and home educators. The worrying thing for me is that we don't have a full set of data.
"Without the number of home-educated children, we don't know their educational outcomes."
The report has sparked outrage from home-education groups, who feel the recommendations paint them as child abusers and will lead to intrusion in their homes.
Many home educators questioned the review's data, with some posing Freedom of Information requests to the Government demanding more information on the evidence submitted.
Cathy Koetsier of the Home Education Advisory Service said: "The figures mentioned in regard to Neets are very peculiar - we don't know where they've come from. Home-educated children do not have a point where they're finished.
"Just because they're 17 and at home doesn't mean they're doing nothing. They could be completing a correspondence course or training not recognised by the Government.
"There needs to be further investigation into the statistics - some seem very strange."