In a submission to the children, schools and families select committee's inquiry into teenagers not in education, employment or training (Neets), the Association of Colleges (AoC) said the Government had identified three groups with different reasons for dropping out of education.
They were: those "open to learning" who may just be taking a year out; the "undecided", who are dissatisfied with the options for learning; and the "sustained", who have few qualifications and a poor experience of education.
The AoC said: "Understanding these reasons better can ensure more tailored and personalised learning programmes and should ensure that problems are addressed early on in secondary school. Our experience suggests that unless these problems are addressed in Years 8 or 9, alienation from education and learning will grow and it is much harder to re-engage such young people."
Its proposal builds on the success of some colleges in offering programmes to keep younger teens in education. About 83,000 14- and 15-year-olds spend some time in college, and 4,500 are already studying full-time.
City of Bath College, for instance, enrolls these students on a course involving basic skills, personal development and a choice of vocational pathway, ranging from refrigeration engineering to hairdressing.
With additional pastoral support, the college has managed to steer 90 per cent of teenagers who complete the course on to a further level 2 qualification.
Leicester College's Launch Pad programme also helps 97 per cent of teenagers with a clear vocational goal to move on to further study or into skilled work.
But the AoC said the calculation of course success rates, which penalise colleges if students drop out, did not provide an incentive to work with hard-to-reach students who might be most at risk of quitting.
It said measures of success should give credit for advances in learning or employment to encourage them in this outreach work.
Number of 14- and 15-year-olds currently spending time in college.