The Welsh government has announced that some A-Level and GCSE grades will be changed.
Kirsty Williams said today that the qualifications will be awarded on the basis of assessments by teachers at the schools the pupils attended.
The move follows outrage over large numbers of students ending up with grades lower than they were predicted to get.
If students received a higher grade than they were predicted, those grades will still stand, she said.
The move should avoid scenes like those last week when many students were left dismayed by the results they got.
It also follows condemnation by North Wales headteachers, who said the system had let down learners.
Mrs Williams said:"Working with Qualifications Wales and WJEC we have sought an approach which provides fairness and balances out differences in the standards applied to judgments in schools.
"Given decisions elsewhere, the balance of fairness now lies with awarding Centre Assessment grades to students, despite the strengths of the system in Wales.
"I am taking this decision now ahead of results being released this week, so that there is time for the necessary work to take place.
"For grades issued last week, I have decided that all awards in Wales, will also be made on the basis of teacher assessment.
"For those young people, for whom our system produced higher grades than those predicted by teachers, the higher grades will stand.
"Maintaining standards is not new for 2020, it is a feature of awarding qualifications every year in Wales, and across the UK.
"However, it is clear that maintaining confidence in our qualifications whilst being fair to students requires this difficult decision.
"These have been exceptional circumstances, and in due course I will be making a further statement on an independent review of events following the cancellation of this year’s exams.
"Other Awarding Bodies across the UK are involved in determining the approach to vocational qualifications. This continues to be the case but it is important that I give assurance to GCSE, AS and A level student at the earliest opportunity."
