Students are being given misleading information and are directed to ill-suited courses, sometimes run by institutions with little experience of the field, according to new research into the increasingly "cut-throat" competition between colleges and schools.
But fierce battles for recruitment in the post-16 market have produced better support for students and more opportunities for ethnic groups and other minorities, according to a paper by staff at King's College, London.
Researchers Stephen Ball, Meg Maguire and Sheila Macrae interviewed staff at seven colleges, two schools and two training and enterprise councils in London, and uncovered evidence of widespread problems.
The work, produced for this week's annual meeting for the British Educational Research Association, provides the first hard evidence of practices like spying, student-poaching and direct copying of courses. One sixth-form college manager even admitted to paying schools Pounds 200 to cover the costs of bringing pupils to see the college.
Their report says: "The behaviour of institutions within our education and training market appears to generate a number of significant inefficiencies and duplications. It produces dis-coordination, encourages segmentation, differentiation and exclusion. It inhibits information flow, it encourages short-termism and it throws up ethical dilemmas.
"On the other hand there are positive outcomes from this market behaviour, for example the development of systems to improve retention, a greater attention to some minority interests, a greater awareness of students with special needs and greater flexibility in the modes of delivery of courses."
The report accuses colleges of enrolling people on inappropriate courses to boost numbers. One tutor is quoted as saying: "We'll take them on intermediate GNVQ courses even if we know they are not up to it, because if we don't someone else will. We know they will drop off. So we encourage them to transfer routes."
The report points to spying. One deputy faculty head said: "Oh yes we always spy, we had to, I'm afraid...often people will go along and see what other colleges are like, see how well we do and see if we can learn anything from them."
Another staff member said: "I don't think anyone really likes it, but we all play the game and fight for every last student we can get."
And a student counsellor told researchers: "It could be argued that it was a bit of a con piling students into these courses that probably won't lead directly to employment, but if we don't put them on others will and the students will take their custom elsewhere. Money, of course, rules and as students mean money we try to supply them with what they want. We follow the fashion to stay in business and hold on to our jobs."
The study also points to barriers put up by schools to discourage colleges from recruiting.
One college executive told researchers: "I shouldn't say it, but I think that it probably isn't in schools' interest to educate their pupils too well about the various options at 16."
But researchers did find colleges willing and able to recruit heavily among groups with special needs, people with poor disciplinary records and those from ethnic minorities.
Colleges were also becoming involved in niche marketing, trying to attract working-class, or ethnic-minority students by focusing attention on the local labour market. Staff pointed out that the 16-19 market was limited, leaving expansion into other areas the only way to increase enrolment.