Many more mathematicians than lawyers gain first-class honours - 22 per cent versus 4 per cent - but that is unlikely to mean they are "cleverer" or that maths is an easier subject than law. So why is there such variation in grades?
Mantz Yorke of Liverpool John Moores University has analysed data on the spread of degree classifications, published this year by the Higher Education Statistics Agency, to try to discover whether different marking methods are the key to the problem.
His research, to be unveiled this week at the British Educational Research Association conference in Leeds, confirms that science-based subjects show a higher proportion of firsts - as well as of third-class grades - than subjects in the arts, humanities and social sciences.
"Our investigations suggested that at the level of the module, the spread of results might, in the more discursive subjects, be influenced by the method of grading," Professor Yorke said. He found that at module level the grade spreads for these subjects tended to be wider in universities opting for grade marking such as A or B as opposed to percentages.
This raises a question about institutional consistency, a particular concern as the Quality Assurance Agency's code of practice emphasises the need for consistency in assessment.
But Professor Yorke's team found that there were no uniform connections to the eventual class of degree awarded. "We understand too little about the way institutions calculate degree classes," he added. "Before we start to make any attempts to regularise what we do in grading students' work, we need to think clearly about what grades truly mean. The data show that spreads of degree classifications vary enormously between subjects, raising challenging questions regarding equity of treatment."
In general, subjects in the humanities tended to award most students a 2:1 grade, with tiny proportions of thirds. In maths, engineering, the physical sciences and computer science, the spread was far greater, with higher proportions of firsts. Up to 16 per cent of mathematicians and engineers are being given thirds, compared with 2 per cent in the humanities.
- The risk of marginalising black and working-class students because of gaps in the curriculum is never discussed, a research fellow at Staffordshire University has said. Jocey Quinn's research suggests that the curriculum validates white middle-class values.