The University of Sussex has dropped out of the top 20 universities in the country in a league table.

The institution, based in Falmer, fell 16 places to 27th in the annual Guardian University Guide.

However, the University of Brighton has risen nine places up the rankings to 64th compared to 73rd last year and 78th the previous year.

In Art and Design it was ranked in the top ten. Sussex said the drop was not “an accurate reflection” of the educa- tion it provides.

The league table is based on experience ratings by first-year students, a value-added score, university spending per student, staffing ratios and graduate career prospects.

A Sussex spokeswoman said the data showed it was in the top ten for both student satisfaction and for how much students benefit from going to the university. She said: “Our fall in this league table is directly related to the heavy weighting given to the score we achieved for “assessment and feed-back” in the 2011 National Student Survey.

"We have now completely reformed how we manage our assessment and feedback, which should make a significant difference to our students.

“We will have a new structure this coming academic year, introducing an exam period in the middle of the year as well as continuing with the traditional one at the end of the year.

“Our focus will continue to be on further developing the high quality teaching and learning and research which Sussex provides to over 12,000 students from the UK and overseas.”

Professor Stuart Laing, the University of Brighton’s deputy vice-chancellor, said he was “pleased” with the university’s developing success.

He said: “As one of the most popu- lar universities in the south-east, Brighton offers an extensive range of academic and professional degrees underpinned by experienced and innovative teaching and world class research.

“Our graduate employment record and National Student Survey results show our courses are delivering what our students require.”