Queen's University Belfast (QUB) has slipped further down the rankings of the world's top universities.
The 2023 QS (Quacquarelli Symonds) world rankings compare the performance of the world’s top 1,400 universities across 100 countries.
QUB had been listed as 216 in global rankings but now sits at 233.
Meanwhile, Ulster University's ranking has improved, going from the 651-700 category last year to 601-650 this year.
The QS rankings use six indicators: academic and employer reputation; citations per faculty; faculty/student ratio; international faculty ratio; and international student ratio.
The ranking criteria for both Northern Ireland universities rank highly for their ratio of international faculty and students. However, QUB has a lower ranking for employment outcomes, while Ulster University has a low ranking for academic and employer reputation, faculty/student ratio and citations per faculty.
Many critics say university rankings are flawed and do not accurately capture the impact of teaching and learning. However, most in the higher education sector acknowledge they remain influential internationally.
In a statement, a spokesperson for QUB said a number of factors are at play.
"University league tables provide useful insight into areas of strength, but different tables use different criteria which means ranking results can vary. Queen's maintained its position as ranked 29thin the UK - and the change in world positioning is largely due to an additional 150 universities being included this year. It is worth noting that 47 UK institutions went down, including 16 Russell Group universities.”
They continued: “Queen’s also saw an increase in demand for students wishing to study here which saw our student: staff ratio (SSR) score being impacted. We are addressing the student staff ratio with strategy 2030, through 100 new academic staff appointments.
"However, as NI universities receive significantly less funding per student than English peers, which impacts on staff numbers, competing with our peers in England will remain a challenge. This underlines the need for a sustainable funding model in NI to address this structural disadvantage."
Overall, Massachusetts Institute of Technology ranks number one globally, while University of Cambridge is in second place and Stanford University remains in third.
In the Republic of Ireland, Trinity College Dublin (TCD) has climbed into the top 100 global universities, while most other Irish universities have slipped down the league table.
TCD is up three positions to 98th position. It's due to a rise in citations — a measure of academic impact — as well as a strong performance in academic and employer reputation surveys, according to the rankings.
University College Dublin (UCD) is down eight places to 181st, while NUI Galway is down 12 places to 270th.
There is also disappointment for University College Cork (UCC), which is out of the top 300 after slipping five places to 303rd place.
Dublin City University (DCU) bucked the trend and is Ireland’s most improved university, climbing 19 places to 471st place.
QUB and Ulster University have been contacted in relation to this story.