The release of class ranking information to Leaving Cert 2020 students via a website has soured relations between the Department of Education and second-level teacher unions.
The Teachers' Union of Ireland (TUI) has accused the department of a "fundamental breach of trust" and said it showed "scant regard for vulnerable students".
The department announced this week that, from next Monday, students can find out how their schools rated them against fellow pupils in each subject via the calculated grades student portal.
On September 14, students had access to both their school's estimated marks as well as the final marks awarded by the calculated grades office.
The manner of the release of the class ranking information has been the subject of a dispute between the department and unions, who were previously told it would be available only on foot of a data access request.
The department held off making it available on September 14, but following legal advice, said it was putting in place a system to allow students to gain access to the information. It is understood the advice centres on the issue of students' entitlement to their personal data.
The TUI said the release of the rankings in such a manner had "the potential to be extremely damaging for more vulnerable students, reinforcing stereotyping and stigmatisation, embedding disadvantage and serving absolutely no useful practical or moral purpose".
The union said it engaged with the calculated grades process on a good faith, once-off basis and sought and received certain assurances, including that the student ranking would only be available to a student in response to a data access request.
"Ranking students in such a manner runs completely counter to the values of inclusive teaching and was only agreed upon on the understanding that it was to improve the accuracy of the data collected and would not be released in the manner now planned.
"The departure from this agreed position is a fundamental breach of trust by the department and is profoundly damaging to the student/teacher relationship."
The response of the Association of Secondary Teachers' Ireland (ASTI) was more muted, although general secretary Kieran Christie recently expressed strong views on matter.
The ASTI said yesterday its "understanding throughout this calculated grades process was that students would be entitled to submit a data access request under data protection legislation and that the school's mark and ranking for the individual would be made available to those who request it. This has been a challenging year for Leaving Cert 2020 students and our hope is that these students can move on with their lives."
Some of the sting appears to have been drawn by the decision not to release the ranking information on September 14. Nonetheless, in correspondence with members earlier this month, Mr Christie said: "This episode constitutes a regrettable breach of trust that will take some time to repair."