Proportion of degrees that are first class rose from 16% to 27% in six years, OfS finds.
The higher education watchdog has issued a stark warning to universities that they will be fined or even removed from the official register if they fail to tackle spiralling grade inflation at degree level.
Research by the Office for Students reveals for the first time the scale of the problem, which is virtually sector-wide with 84% of universities seeing significant unexplained increases in the number of first-class degrees awarded.
Overall, the proportion of first-class honours awards has risen from 16% of all degrees awarded in 2010/11 to 27% six years later, according to OfS analysis of results at 148 universities and higher education providers.
At the University of Surrey the proportion of firsts has more than doubled, from 23% in 2010/11 to 50% in 2016/17, while at Bradford University it has almost tripled, from 10.6% to 30.9%.
The OfS, which is the new regulator of the higher education sector in England, called on universities to take urgent action to address the problem and warned of severe sanctions if they failed to do so.
Nicola Dandridge, the OfS chief executive, said: “This report shows starkly that there has been significant and unexplained grade inflation since 2010-11. This spiralling grade inflation risks undermining public confidence in our higher education system.”
According to the OfS regulatory framework, one of the conditions of functioning as a university is that “qualifications awarded to students hold their value at the point of qualification and over time”. If a university is found to be in breach of the condition, it may be fined, suspended from the register or deregistered altogether.
Ministers have become increasingly concerned about the growing proportion of firsts and upper-class second degrees being awarded at universities. According to the latest research, the proportion of firsts and 2:1s combined has increased from 67% in 2010/11 to 78% six years later.
The education secretary, Damian Hinds, called on the OfS to crack down on institutions found to be inflating grades. “I sincerely hope today’s figures act as a wake-up call to the sector, especially those universities which are now exposed as having significant unexplained increases,” he said.
“Institutions should be accountable for maintaining the value of the degrees they award. I am urging universities to tackle this serious issue and have asked the Office for Students to deal firmly with any institution found to be unreasonably inflating grades.”
Guardian Today: the headlines, the analysis, the debate - sent direct to you
Increases in first-class degrees among students entering university with lower A-level results are particularly striking. Graduates who achieved the equivalent of two Cs and a D were almost three times more likely to graduate with first-class honours in 2016/7 compared with six years earlier.
There is no parallel increase in degree attainment among graduates with top A-level results, and in the main it is the institutions with lower entry tariffs where the highest unexplained increases have been found.
Universities have defended themselves in the past, saying the sector has changed significantly with more emphasis on the quality of teaching, alongside the fact that with higher tuition fees students are working harder to achieve higher grades.
The OfS has used statistical modelling at the individual student level to try to account for factors that might influence attainment. It concludes that a significant element of the increases cannot be explained by changes to the graduate population and attainment and therefore remains cause for concern.
Across the sector as a whole, the OfS found that 11.6 percentage points of the increase in first-class degrees awarded between 2010-11 and 2016-17 were unexplained, though in some universities the figure is much higher. At Surrey it is 27.3 percentage points; other universities where there are relatively high unexplained increases include Huddersfield, Greenwich, Coventry and Essex.
Dandridge said it was crucial that degrees held their value over time. She said she recognised how hard students worked for their degrees and accepted that improved teaching, student support and pre-university qualifications could explain some of the increase in grades.
“However, even accounting for prior attainment and student demographics, we still find significant unexplained grade inflation,” she said. “This analysis may make uncomfortable reading for some universities. It shows that individual and collective steps are needed to ensure that students can be confident that they will leave higher education with a qualification that is reliable, respected and helps ensure they are ready for life after graduation.”
Alistair Jarvis, the chief executive of Universities UK, which represents 137 universities, said the sector was already taking steps to tackle grade inflation. “It is essential that the public has full confidence in the value of a degree,” he said.
Of the 124 universities (84% of the sample) with significant unexplained increases in the number of first-class degrees, 77 showed a statistically significant unexplained increase relative to both the sector and their own level in 2010-11. A further 28 showed a statistically significant unexplained level of attainment above that of the sector level, and 19 showed a statistically significant unexplained increase relative to their own level in 2010-11.