Auckland University has inched up two places in the latest global rankings - but Waikato University has plunged by more than 100 places in the biggest tumble that any New Zealand university has suffered under the current ranking system.
The latest Quacquarelli Symonds (QS) rankings, released in London overnight, retain Auckland University as New Zealand's highest-ranked university at 81st in the world, its highest ranking for five years.
Massey University and AUT (Auckland University of Technology) have also risen in the ranks to 272nd and 437th respectively, although AUT's limited research base due to its origins as a technical institute still place it last among New Zealand's eight universities.
But our five other universities have all dropped: Otago down eight places to 184th, Canterbury down 43 to 270th, Victoria down eight to 223rd, Lincoln down 31 to 387th - and Waikato down a massive 109 places to 375th out of the 1000 universities on the list.
Waikato's biggest drop is in "citations per faculty member" - a measure of how often research by the university's academics is quoted in the world's leading academic journals.
Last year Waikato climbed from 92nd to 72nd in the world on this measure, but this year it has fallen back to 309th.
In 2017, when Waikato first jumped on the same measure, Vice-Chancellor Professor Neil Quigley said his academics were expected to "make a contribution to the international literature".
"That is our job - to be producing innovative work and communicating it not just to our students in the classroom and through local channels, but in the international literature," he said then.
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Universities NZ chief executive Chris Whelan said there was "always a bit of noise" in the rankings because of the way they were compiled.
"A significant part of the QS rankings come from an academic reputation survey which varies from year to year depending on which academics fill it out," he said.
"They are asked to list the top universities in their field. It's a 40-minute survey and a lot of academics lack the will to fill it out, and so you tend to get a bit of variation.
"In some years when New Zealand has held a major conference in a particular discipline we've jumped 20 places, and in other years when no one has been able to attend conferences that year we are suddenly out of mind.
"We have seen a bit of that this year. Some universities have seen a bit of a drop. We generally don't mind too much moving 20 or 30 places when you have 500 universities in the list. It's the long-term trends that matter."
The rankings are based on scores for the academic reputation survey (40 per cent), citations per faculty member (20 per cent), teacher/student ratio (20 per cent), a global survey of employers (10 per cent), the proportion of foreign academics (5 per cent) and the proportion of foreign students (5 per cent).
NZ universities generally rank highest on the proportions of foreign academics and students, and lowest on staff/student ratios.
Auckland University, however, earns its highest rating (59th) for its academic reputation. Its improvement this year was driven by a slightly better staff/student ratios and a big jump in citations per academic, from 330th in the world to 243rd.
Quigley said Waikato University's drop was "a reflection of some very highly cited papers no longer falling within the census period".
"The university's research overall continues to be well cited, reflected by the fact that we are third in New Zealand for citations," he said. "We have remained consistent in all other categories."