I remember a conversation I had once with a colleague, a respected teacher and principal teacher of history.

“I hear Jane Smith got full marks in that modern studies essay you gave her,” he enquired.

“Yes, great piece of work, top drawer,” I replied.

He came back to me: “I never give more than 18/20 for an essay. I’ve never given full marks in my life. They get complacent if you give them full marks.”

“Alexa’s a smart lassie. If you give her 18/20, she’ll know that’s full marks from you,” I said.

He never had a reply to that. I told him to go and watch This Is Spinal Tap.

The Scottish government has accepted that it had a flawed process for allocating this year’s grades. When the Scottish Qualifications Authority (SQA) saw that Higher pass rates, in a year of a global pandemic with teaching interrupted, had gone up 14 percentage points, it slammed on the brakes. SQA was right to question the optimism, shall we say, of these predictions.

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However, the moderation process was implemented in a crude and unfair way with the result that high-achieving youngsters from less high-achieving schools were penalised by the results of previous cohorts. But what of youngsters whose teachers - like my former colleague - were not “optimistic” in their predictions, but pessimistic?

SQA results: Are teacher predictions now infallible?

Not all teachers are glass-half-full - some see a half a void in their tumbler. Anecdotal evidence would suggest that there’s more than a few parents knocking on headteachers’ doors asking why the “academic judgement” of a prelim grade was seen as the be-all and end-all in their school prediction.

The SQA instructed teachers and centres to predict youngsters’ grades “holistically”, taking into account not just past evidence but anticipated improvement as a result of feedback, growing maturity and the inevitable cramming and focus that SQA exams bring.

The problem is that the SQA has stated that its new appeals process would not apply where “academic judgement” is wrong. There are youngsters out there - not as many as in round one, but still numerous - who have been disadvantaged by low-ball predictions which, as it stands, cannot be appealed for.

The SQA knows that relying solely or overwhelmingly on a prelim result is unfair. Past achievement, including prelims, can be a very unreliable instrument of predicting a youngster’s likely attainment.

National 5 prelims are usually taken in November of the academic year and sample only a section of the overall course. There’s quite a way to go before the exams in May. Higher prelims are usually done in January of the year. Despite Curriculum for Excellence, we still have a “two-term dash”, and a prelim can’t be used to predict with unflinching certainty.

This isn’t a slur on the professionalism of teachers. In some subjects there can be wide variations in what two teachers would award and both could be right. Some teachers, with the best of intentions, do mark more severely at prelims than at other times. The prelims were undertaken pre-Covid and teachers have in the past used these exams almost to emphasise student mistakes and mark them down to motivate youngsters not to make these mistakes in the “real” exam. It works with some youngsters.

The prelim may also have sampled the parts of a course a student isn’t best at. And something that isn’t always recognised is that some candidates are younger than others. Some S5 Higher candidates will barely have turned 16 when sitting their prelim. Those four months after the prelim and before the exam are crucial periods in their development.

Good teachers use prelims to flush out strengths and weaknesses. Give feedback and encouragement. Perhaps make decisions about actual presentation at a particular level. Prelims were never designed, not this year anyway, to be the basis of a student’s eventual grade.

All in all, it seems to me to be harsh of the Scottish government and the SQA to rule out “academic judgement” as a basis for appeal. Is SQA now saying that teacher judgement is infallible? That all teachers mark to the national standard at all times? If so, it can safely do away with its external verification system.

Last week SQA accepted that youngsters whose grades were downgraded deserved a fresh chance. There are still some students out there who aren’t getting that opportunity. If a teacher overpredicted, which SQA believe happened, great. But if they underpredicted - tough. That doesn’t seem fair.

Given the unique circumstances of Covid, which John Swinney so eloquently explained in the Scottish Parliament, a realistic appeals procedure would be greatly welcomed by students and parents, who deserve a fresh look at how grades were processed. If a student feels they were underpredicted in this crazy, unprecedented year, then let the SQA decide.

John McTaggart is director of www.modernity.scot and teaches on the University of Glasgow PGDE modern studies course. He is a former teacher and SQA examiner, and tweets @modernityscot