Predicted grades provided by schools will be used to decide results for pupils in Northern Ireland who take A-Levels through English exam boards.
Schools will take into account things such as classwork, homework, coursework and mock-exams in and are being asked to rank their pupils in each subject.
Exams have been cancelled after schools shut due to coronavirus.
Results will be compared centrally to take account of the fact some schools grades may be too generous or harsh.
About one-in-eight A-Level entries in Northern Ireland are through exam boards elsewhere in the UK.
A small minority of pupils (2%) also take GCSEs through other UK boards.
There are to be no written GCSE, AS or A-Level exams across the UK due to the coronavirus pandemic.
However, it will be up to Education Minister Peter Weir to announce specific arrangements for exams and grades in Northern Ireland taken with the local exam board, the Council for the Curriculum, Examinations and Assessment (CCEA)
The vast majority of entries at GCSE, AS and A-Level in Northern Ireland are through CCEA.
Ofqual, the regulator for exams and assessments in England, has published new guidance for the awarding of GCSE and A-Level grades this summer.
It will also apply to Northern Irish pupils who take exams through AQA, Eduqas, OCR and Pearson.
Qfqual said schools and colleges would provide information needed for the exam boards to award grades.
In a letter to students, Qfqual said schools would be asked to provide two pieces of information to enable grades to be awarded.
The first would be a "predicted" grade and the second to rank pupils' performance within each subject.
Schools are being asked for "the grade they believe you were most likely to get if teaching, learning and exams had happened as planned," the Qfqual letter said.
Secondly, "within each subject, the order of students at your school or college, by performance, for each grade.
"This information will be used to standardise judgements – allowing fine tuning of the standard applied across schools and colleges.
"Your school or college will consider a range of things like your classwork and homework, your results in assignments and any mock exams; any non-exam assessment or coursework you might have done and yourgeneral progress during your course."
Autumn exams possible
Ofqual said it would compare and standardise grades across schools to take account of the fact some schools might be more generous or harsh in predicting grades than others.
Pupils were also told that teachers would not be allowed to tell them the grades which schools had submitted for them.
Ofqual also said that A-Level, GCSE and AS results were planned to be given out as normal in mid-August or possibly "a little earlier."
They also said it was possible that physical GCSE, AS and A-Level exams could take place in the autumn for those unhappy with their summer grade.
Meanwhile, CCEA said Mr Weir would decide how GCSE, AS and A-Level results would be awarded for their qualifications.
"We understand the urgent need for clarity for both students and teachers, and plan to rapidly implement the arrangements, once these are set out by the minister of education," a spokesperson said.
"We will also publish the process that we will follow to ensure grades are fair across all schools and colleges in Northern Ireland.
"We want to reassure students, parents and teachers that we are doing everything we can to ensure that the full attainment of all students is fairly recognised, during this unprecedented time."