Solely using teacher estimates to allocate A-level grades in Northern Ireland would lack any level of credibility, the education minister has insisted.
Giving evidence to his Stormont scrutiny committee, Peter Weir resisted calls to scrap the results allocated to pupils using a standardisation calculation model and replace them with the grades predicted by their teachers.
More than a third of A-level grades issued on Thursday were lower than teacher estimates.
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In 37% of cases teachers were over-optimistic in their prediction, while in around 5% of entries they under-estimated the result.
Overall, the percentage of top grades allocated in 2020 was up on previous years.
However, many students have been left shocked and disappointed after receiving grades that were significantly lower than both their performance in previous exams and their teachers' prediction.
Committee chairman Chris Lyttle urged the minister to intervene and ensure pupils were awarded grades based on either their AS-level attainment or the estimated grade assessed by their teacher.
"These are unprecedented times," he said.
Mr Lyttle said he was aware of a school that had seen its A*-C attainment rate fall from 90% last year to 60% under the calculation model.
He said the minister was "increasingly isolated" in refusing to use the teacher assessments to allocate the grades.
Mr Weir responded by insisting that if teacher predictions were used without standardisation, the results would not have "any level of credibility" because the results would be so much higher than those achieved in previous years.
He said that approach would also be unfair on pupils, as some teachers would have been "generous" in estimating grades while others had been "tough" on their students.
"There would be no equality whatsoever," said Mr Weir.
The minister acknowledged that the system for calculating A-level results "did not work for everyone".
He said there was no way of creating a perfect replacement for sitting the exams which were cancelled as a result of the coronavirus pandemic.
"We were looking to create what was a least-worst solution," said the minister.
Mr Weir highlighted that a fast-tracked appeals process has been established for those students who believe they have been treated unfairly.
The standardisation model was developed by Northern Ireland exam body the Council for the Curriculum, Examinations and Assessment (CCEA).
CCEA asked teachers to give a predicted grade for their pupils and then rank them in order within their class.
The exams body then used other data to standardise the results.
For A-levels, the data included pupils' AS-level results, making adjustments for those who had applied to take resits.
For AS results, the pupils' GCSE results were also used, as was the performance by their school over the previous three years.
SDLP member Daniel McCrossan branded the situation a "debacle".
He expressed concern about the mental health impact on children, revealing that a GP had contacted him to alert him that three pupils who had missed out on university places had presented with suicidal thoughts.
"This model failed, it failed our children and it failed our young people," he said.
He added: "As the result of this pandemic, they should not pay the price."
Mr McCrossan demanded more transparency on the algorithm used to calculate the grades.
Sinn Féin MLA Catherine Kelly urged Mr Weir to follow the example of Scottish education secretary John Swinney and replace the disputed standardised results with teacher estimated grades.
"Why can you not show the same leadership and show that young people are at the very heart of decision-making going forward?" she asked.
The MLA called on the minister to "reverse this shambles", insisting the judgment of teachers had more credibility than a "mystery algorithm".
Mr Weir made clear he would not be replicating the move by the Scottish government.
"I think the Scottish decision was wrong," he said.
CCEA chief executive Justin Edwards also faced questions at today's lengthy hearing.
He defended the model used, insisting a range of academics and other experts were involved in its development.
Mr Edwards stressed the limited time his organisation had to deliver on the minister's key objectives - to produce a set of results for the 2020 cohort and to ensure standards were in line with previous years.
"People have worked inordinate hours in my organisation to deliver a solution," he said.
"I've always cited that the best solution was examinations and it was not available to us. And if it was not available to us, then this alternative approach was the next best operation."
He claimed no better solution had been presented, adding: "If there was a viable alternative to this situation, then let it be brought forward."
