Every student who logs on to receive their Leaving Certificate results today has been at the centre of a massive and unprecedented national experiment.

Just six months ago, at the beginning of March, the idea of cancelling the June Leaving Certificate exams, and putting in place an alternative system for this year's cohort, would have been unthinkable.

It was students themselves before most others who grabbed hold of the idea and planted it in the public mind. They pushed and argued, and insisted that their voices be heard.

And by early May the unthinkable had happened: A system of calculated grades was announced.

How were calculated grades arrived at? 

The calculated grades process is a layered one. It began with teachers in schools. They were asked to estimate a percentage mark for every one of their students and also to rank their students in order of likely Leaving Certificate attainment.

Irish teachers had never done this before. They were warned of their potential biases, for instance that research showed teachers more likely to overestimate the marks of a student who was well behaved in class.

The teacher’s marks and rankings were then collated by the school and sent to the Department of Education.

Then the process of national standardisation began.

The predictions from schools were combined with a second set of data: Junior Certificate results.

Junior Cycle results were used in two ways. Using data from students in previous years a statistical model was created to estimate how a student with a particular profile of Junior Cert results was likely to perform in the Leaving Cert.

Secondly, the Junior Certificate attainment of the class of 2020 was used, in aggregate form at school level.

The two sets of data were important, but both were incomplete. Just as school predictions can be flawed, so too can Junior Cycle data.

Research shows that while Junior Cert results are good predictors of Leaving Cert results, they are not strong enough by themselves to estimate an individual’s performance. For this last reason, it was decided that no individual’s calculated grade would be determined by how they had performed at Junior Cycle.

This is where it gets mathematically complicated, and to a level far beyond that even of Higher Level Leaving Certificate Maths. These two datasets, the marks and rankings from schools, and the aggregate Junior Cycle results, were combined to produce calculated grades.

The process inevitably saw some marks awarded initially by teachers lowered, others raised. This is because some schools will have marked more generously compared to others, others more stringently.

But the rank order given to students in a class remained, and the system paid particular attention too to 'outliers' or students who were way ahead of others in their class, or way behind.

The department has said the process ensured that those gaps were not reduced.

With the marks estimated by teachers as a "central pillar" of the process, the department said that standardisation was built on the premise that estimated marks should only be adjusted when there was "credible statistical evidence to justify change".  

There were other checks and balances too. If a student’s grade was reduced by two grades or more for instance (as was the case for just 0.1% of students), then the Department of Education went back to the school data to check it again.

Why was standardisation needed in the first place?

To this question, the Department of Education returns again to the fact that many teachers overestimated marks for their students, giving them what they might have received on a "good day" with the "right questions" appearing on a paper. Others underestimated. All this is natural and was expected.

The level and extent of this varied between schools, and between subjects within schools. It says no standardisation would have led to unfairness to some students and schools.

Results are up but some students have lost out

Home-schooled Mayo student Elijah Burke went to court to have the decision to refuse him entry into the calculated grades process reversed and he was successful.

But there are many other students who have been excluded from the process too. Some are students who hoped to repeat some or all of their exams, but who were working alone without a teacher.

Others are students who are native speakers in a language and didn’t need the help of a teacher. All of these students had no teacher who could provide an estimated mark.

Going through the aggregate data provided by the department, some of these students are visible in their absence.

There were 893 students hoping to sit Polish as a non-curricular Leaving Certificate subject, but just 427 received a calculated grade in the subject.

Across the other mother tongue languages, it’s a similar story. More than two-thirds of applications for a grade in Latvian rejected, from 64 applications, just 19 were successful.

Numbers sitting Lithuanian fell from 167 to 82, Romanian 408 to just 209.

Out of applications from around 1,900 students for a calculated grade in their non-curricular mother tongue, more than half had their application rejected.

Many of these students will have been greatly relying on a strong grade in their native tongue for their CAO points. They are among those who have lost out as a result of the calculated grades process.

What next for students?

There will inevitably be students who are disappointed, or who have questions about their own results.

Most schools have made arrangements for students to phone or drop in to talk to a guidance counsellor or a teacher.

The Institute of Guidance Counsellors is also running a Leaving Certificate helpline, staffed by qualified and experienced guidance counsellors. The number is 1800-265-165.

On 14 September, students will be able to see the marks their school signed-off on for them, as well as the actual percentage mark behind their grade.

There is an appeals process, but a student cannot appeal the mark given by the school, just how that mark was processed subsequently.

The department had intended that students would also be allowed to see the ranking that their school awarded them.

However, following objections from the teacher unions, who say teachers had been assured that information would not be revealed, the department now says that it is seeking legal advice on the matter.

Of course the exams have not actually been completely cancelled. They will be held in November.

It is open to any student to sit the exams this year. And then they can choose then between two grades, taking whichever one is higher.

This of course will be too late for this year’s CAO process. The CAO’s first round of offers will be made this Friday.