An independent regulator is to investigate how more than 150 A-level students in Northern Ireland were awarded lower grades than they achieved.
The grading errors occurred last week after 935 chemistry papers from 41 schools and colleges in Northern Ireland were marked incorrectly.
The Office of Qualifications and Examinations Regulation, which oversees work in England and Northern Ireland, has been asked to review the results process.
Education Minister Caitriona Ruane said: "Students, their parents, teachers and the wider community need to have confidence in our examinations systems.
"This investigation is the first step towards the CCEA (Council for the Curriculum, Examinations and Assessment) regaining that confidence."
The office will look specifically at the chemistry failure, then conduct a wider review of processes and practices within the CCEA, which was in charge of producing the chemistry results.
The findings and recommendations will be made public, with the first report expected by the end of September.
The CCEA said it was confident none of the 151 pupils who received the wrong grade would miss out on a university place as a result of the mistake. It ordered an internal investigation.