The Association of Colleges (AoC) said it would be a "waste of public money" and schools should only be rewarded for "positive outcomes".
It also raised concerns that students who fail to complete courses could be "falling through the gap" of post-16 education.
The organisation, which represents colleges across the UK, published data, obtained through a Freedom of Information request, which appears to show that the results of many exams and courses sat by school and academy pupils are unknown.
The provisional data suggests that the success rates for 23 per cent of exams sat by academy pupils aged 16 and over in 2008/09 are unknown, along with 16 per cent of exams sat by school sixth-formers, and 20 per cent sat by City Technology College pupils aged 16 plus.
AoC director of education policy Joy Mercer said: "There's so much on the outcomes that's unknown. It's not good value for money. Colleges only get funding on positive outcomes.
The AoC is holding its annual conference in Birmingham this week.