A growing number of schools are expressing concern that many A-level results students are receiving “not a fair or accurate reflection”, it has been claimed.
It comes as official figures show A-level results slightly increased in Wales since last year, but grades were much lower than predicted.
Thousands of students across Wales received their "standardised" A level results on Thursday after their summer exams were cancelled due to the Covid-19 pandemic.
This came after last minute changes as the education minister confirmed that no student receiving A-Level results would be awarded a grade lower than their previous AS grade.
The Joint Council for Qualifications said the provisional A-level and AS results in Wales were broadly similar.
The "standardisation" process has meant despite assessments fro teachers that pupils would achieve 40.4% of A* - A grades, just 29.9% of students did.
Figures show that more than 12,800 pupils had their A-level grades lowered - but the education ministers' announcement that pupils would not be awarded anything lower than their AS levels, may have benefitted some of these students.
99.9% of pupils were predicted by teachers to achieve A-E, but the results show that was 98.6%.
Qualification Wales said ''considerable effort'' had been made to ensure the standardisation approaches were '''accurate, robust, and fair as possible'' in the circumstances.
A-A*29.9% achieved A*-A for A level - a rise of 2.9% from last year.
A*-E98.6% achieved A*-E -up 1% from previous year year.
A-A*22.2% have achieved grade A for AS - up 1.9%.
A*-E91.4% have achieved grade A-E -a rise of 1.4%
Kirsty Williams MS said she's confident that the A-level grading system is fair and robust and the changes make sure Welsh students are not "disadvantaged" when applying for university.
Student Bradley Desmier from Merthyr College told ITV News he was "disheartened" after he received grades lower than what he hoped.
He said, "For Drama, I was predicted a C and I got an E, for Photography, I was predicted a B but I got a D and for Applied Science, I was predicted a Merit but I got a Pass.
"It's quite offensive - I was trying to work hard and to receive these, it is quite disheartening."
"Frustration, confusion, and disappointment"
It comes as both England and Scotland were forced to rethink their own marking systems due to concerns students would receive lower than expected marks.
Qualifications Wales acknowledged that the standardisation of grades would never be "perfect".It said: ''The Centre Assessment Grades (CAGs) submitted by schools and colleges were optimistic and, without standardisation, would have produced atypically high outcomes. This would have been contrary to the aim of achieving broadly similar national outcomes to reduce the risk of unfairness.''
But, a leading teaching union has criticised the "devastating impact" of standardising grades and has called for an urgent review.
Eithne Hughes, Director of the Association of School and College Leaders (ASCL) Cymru, said: “While there has been an overall increase in top grades, we are very concerned that this disguises a great deal of volatility among the results at school and student level.
“We have received many calls from school leaders expressing their frustration, confusion, and disappointment at the results awarded to their students. They report that grades have been pulled down in a way that they feel to be utterly unfair and unfathomable, and they are extremely concerned about the detrimental impact on the young people concerned."
Head teacher Neil Foden has also warned students in Wales risk being "short-changed" by an A-level system that is "not fit for purpose".
"There is real concern in schools about the number of learners whose results have been downgraded from the teacher estimates," he said.
"This is already the generation whose wellbeing and, in some cases, mental health, has been affected by lockdown and concerns about Covid-19.
"Now they are the generation who could be short-changed by a statistical model that is clearly not fit for purpose.
"The appeal process in Wales could take eight weeks. In the meantime, our university candidates are expected to go cap in hand to universities to ask them to be ‘flexible’ while appeals are resolved."
Analysis from ITV Wales reporter Megan Boot.
It’s hard to convey just how emotional today has been for teachers and students. A-level results day is always emotional, but it’s particularly hard when you haven’t had a chance to sit your exams and the grades you get don’t reflect the ones you’ve been expecting. One teacher told me this morning, that they didn’t know how they were going to be able to look their students in the eye.
In order to get today’s results, teachers had to submit grades to the exam board for standardisation. Today, it’s been revealed that 12,845 grades were then lowered - whilst 1,255 were increased. Those figures may change though - as they don’t take into account the last minute decision from the Welsh Government to ensure no one’s A-level grade would be lower than their AS grade. But, it brings into sharp focus a huge question - who is right here the teachers, or the regulators?
The education minister says 94% of the grades given today are the same level or within one grade of the teacher's assessment. She also added that it’s important grades are standardised to ensure today’s grades are of equal value to years gone by. But, the National Education Union have said from their contact with schools so far today, 90% of head teachers are unhappy with their grades.
For those hoping to go to university, the big test is whether these grades will still get them their places. Initial figures from UCAS this morning suggest a record number of acceptances for Welsh Students. But as today has shown, this isn’t so much about national figures - but individual stories.
Can I appeal my awarded grade?
Students are advised to first talk this through with their teacher or the exams office in their sixth form or college - they are the ones who appeal on the student's behalf.
If the college or sixth form agree to appeal, it can take up to 42 days for the WJEC to review that application. This means that you should submit the appeal as soon as possible if you are waiting to confirm a university place.
The final deadline to apply for an appeal is currently 17 September 2020.
Grades can go up, stay the same or even go down following an appeal. Ms Williams also confirmed that the appeals process would be free for students.
First Minister Mark Drakeford posted a message on Twitter for students picking up their grades, praising them for their efforts during a 'difficult situation'.