Soaring grade inflation “risks undermining public confidence” in the higher education system, the Office for Students (OfS) has warned.
The regulator said universities must take urgent steps to tackle the issue after publishing data that suggests there has been a significant increase in the proportion of first and upper second class degrees being awarded in England.
According to the OfS, the percentage has increased from 67% in 2010-11 to 78% in 2016-17, while the percentage of first-class degrees has increased from 16% to 27%.
The analysis indicates the increases cannot be fully be explained by factors linked with graduate attainment.
Nicola Dandridge, OfS chief executive, said: “It is fundamentally important - for students, graduates and employers - that degrees hold their value over time.
“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.
“We absolutely recognise how hard students work for their degrees, and accept that improved teaching and student support, and increases in the qualifications students gain before university, could explain some of the increase in grades.
“However, even accounting for prior attainment and student demographics we still find significant unexplained grade inflation.”
Education Secretary Damian Hinds said: “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.
“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.”
The report also looks at individual findings for 148 universities and other higher education providers in relation to first-class degree attainment.
It suggests that more than half of the providers (52%) show a statistically significant unexplained increase relative to both the sector and their own level in 2010-11.
A further 19% of providers showed a statistically significant unexplained level of attainment above that of the sector level in 2010-11, but no significant change relative to their own level in 2010-11.
Ms Dandridge concluded: “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, chief executive of Universities UK, said: “Universities are already taking steps to tackle grade inflation.
“The report we recently published outlines a number of measures to protect the value of qualifications over time that are currently being consulted on by the UK Standing Committee for Quality Assessment.
“It is essential that the public has full confidence in the value of a degree.”