by Michael McHugh, PA
A broader scope for appeals will be allowed following this year's A-level and GCSE awards, Northern Ireland's exams body said.
Exams were cancelled due to the coronavirus pandemic and calculated grades will be used to give pupils their results.
A-level awards based on teachers' predictions and statistical modelling are due to be delivered on Thursday.
Council for the Curriculum, Examinations and Assessment (CCEA) chief executive Justin Edwards said: "This year, due to the alternative arrangements it is not possible to ask for examination papers to be reviewed as would be normal.
"We recognise that there is robust evidence available on student prior performance and that this could be considered within the appeals process.
"The opportunity for schools and colleges to submit mock examination information and completed GCSE units provides a broader scope of evidence for appeal."
Schools and colleges may hold strong evidence of students' prior performance from mock examinations and, for GCSE examinations, some completed units, CCEA acknowledged.
It added: "As part of the appeals process this year, CCEA will consider such evidence."
Challenges will be free this year in light of the exceptional circumstances.
Teachers were asked to predict the grades they thought pupils would have achieved had exams gone ahead.
They based that on coursework, mock exams and homework.
Schools were also requested to rank pupils in each subject.
CCEA has standardised results so this year's grades are of equal value to those awarded in previous years.
In Scotland, the government reversed the downgrading of almost 125,000 students' calculated results based on teachers' forecasts.
Stormont education minister Peter Weir said: "This has been an incredibly difficult year for all of our pupils, and in particular for those taking GCSEs, AS and A levels.
"I have made it clear that I do not want to see any pupil disadvantaged as a result of the Covid-19 pandemic.
"At the same time, it is important that qualification standards are maintained."