Education Minister Norma Foley breached commitments to keep the 2020 Leaving Certificate fair and accurate by not including historical school data in the calculated grade process, the High Court has heard.
The claim was made by lawyers during the first day of the hearing of the lead challenge brought by a Leaving Cert student against the calculated grades process and awarding of college places for 2020.
Feichín McDonagh SC, for Freddie Sherry, said the minister had "jettisoned" her commitment to keep the process of estimating grades fair by opting not to include historical data about schools' past performances.
The minister's decision, counsel said, had also resulted in inflated grades and had breached a second commitment to making the 2020 results comparable to those in past and future years.
Counsel said the process adopted by the minister was not panicked or rushed.
Considerable expert opinion was obtained as to the best way to fairly and accurately assess calculated grades.
Counsel said following what was a "top-down intervention" by the minister, it was decided not to include historical past data from previous years' performances by schools when it came to assessing grades.
There was no requirement to exclude that data as part of the grade assessment process.
In addition, the system being used to calculate grades in Ireland was different to those used in the UK, where there had been wide-scale criticism after thousands of results were marked down to reduce grade inflation.
Mr Sherry, who sat his Leaving Certificate at Dublin's Belvedere College SJ, is the test case of around 50 challenges by other Leaving Cert students against the calculated grades process.
In his action, Mr Sherry, of Newtown, Celbridge, Co Kildare, claims a direction by the minister last August to remove school historical records in the calculated grades process resulted in him being unfairly downgraded by 55 points in his Leaving Cert.
Mr McDonagh said his client was hugely disappointed when his teachers' estimated CAO points total of 542 for him was reduced to 487 under the process.
He missed out on his first course choice of pharmacy at Trinity College.
The minister and State deny the claims and maintain there is no reason to believe Mr Sherry would be in an improved position if historical school data was included.