A-LEVEL results published tomorrow are expected to show a drop in the number of pupils taking the core subjects of English and maths.
Entries overall are expected to fall, with sixth-formers also avoiding foreign languages and fewer taking physics, chemistry and biology.
The high point for entries was reached in 2012 and they have been in decline since then.
There will also be no surprise if there is a dip in overall performance.
Last year's 30.7 per cent was the lowest proportion of top grades since 2004 but was still higher than the rest of the UK, where 26.3 per cent were given A or A* grades.
The Council for the Curriculum, Examinations and Assessment (CCEA) said there are more pupils staying on for sixth form now compared to previous years. This means the ability range has changed.
While the actual numbers scoring top marks is likely to remain roughly the same, there are now more pupils entering who are achieving lesser grades, pushing the overall percentage at the top down.
Provisional data released by Ofqual last month showed the number of pupils studying A-level politics and religion had dropped sharply.
The huge fall in entries for political studies comes at a time of growing dissatisfaction among young people with the north's politicians.
Falls were also predicted in English, maths, languages and the sciences.
Those figures represented the number of entries submitted by schools and colleges to exam boards in Britain and Northern Ireland by April 21 2014.
Schools could continue to make late entries right up until the day of the exam, but the final figures published on Thursday are not expected to be significantly different.
CCEA has set up a dedicated examinations helpline, meanwhile, offering advice and guidance for the thousands of students expecting both A-level and GCSE results over the next fortnight.
It will be in operation from 9am until 5pm, from today until Friday August 29, but lines will open early at 7am on results days.
Anyone with queries regarding CCEA's examination results can call 028 9026 1260, email helpline@ccea.org.uk, or log onto the CCEA website www.ccea.org.uk to search for answers from the frequently asked questions section.
"Results day is an important time for students, their families and schools. At CCEA we would like to reassure all those awaiting results that there is help at hand should you need guidance or assistance. CCEA's experienced staff will be providing a helpline service throughout the results period, operating from 13 to 29 August," examinations manager Michael C r o s s a n said.
"This service can provide useful information to aid decision making about the next steps.
"I would like to commend all students on the hard work and time spent preparing for and completing GCSE and A-level qualifications. I wish them every success with their future plans, whether they choose to go onto further study or employment."