Older undergraduates and women do better across a range of university subjects than teenage schoolleavers and men, according to analysis from two universities.
Also, state-educated students tend to fare better than those from public-school.
Mantz Yorke, professor of higher education at Liverpool John Moores University, said older students outperformed in a quarter of subject areas studied, mainly in those where life experience would be an asset, including healthcare, education and psychology. Younger students tended to shine in business studies and information technology.
The study, based on more than 30,000 module results from 4,300 full-time students at institution A and 8,600 results from 1,500 students at institution B, found that performance of the over and under-20 age groups was more or less comparable in the other three quarters of subjects studied.
The study provided evidence that female students performed better than male. At institution A their performance was better in 15 of 23 subjects and in eight of 20 subjects at institution B in the 2002-03 academic year.
Professor Yorke said: "The 'gender gap' was present whatever form the module assessment took - wholly by exam, wholly by coursework or by some combination of the two. It challenges the assumption held by some that while coursework-based assessment favours females, exams favour males."
The analysis showed students from independent schools performed less well in 12 of 23 subject areas considered at institution A. They included English, geography, psychology, information technology and biological sciences. In one area was the reverse true. There were no comparable figures for institution B.
Professor Yorke said he suspected this could be the result of independent students being spoon-fed at school and therefore less able to cope with the "rough and tumble" of higher education.
The analysis also concluded that students from geographic areas designated by the Higher Education Funding Council for England as "low participation" performed just as well as their counterparts from areas with greater higher education participation, except in subjects involving maths or IT.
The researchers presented their findings at the Student Assessment and Classification Working Group workshop in Wolverhampton on Thursday.