What went wrong with the new Higher Maths paper?
The pass mark for exams is not always 50%.
Each year the exact pass mark and the marks needed for individual subjects are agreed after the papers are marked.
This is a safeguard against the inevitable risk of an exam turning out to be a little easier or harder than those set in previous years.
It is designed to ensure consistency within the system.
The pass mark and grade boundaries can be revised up or down.
For instance, in the old Higher history this year candidates needed 54% to pass and 72% for an A while in English they needed 49% to pass and 65% for an A. In the new Higher English, the pass mark was 56% and candidates needed 74% for an A.
Variations like these are, simply, par for the course.
However to reduce the pass mark to 34% is truly exceptional and suggests a serious failure of the system.
There are essentially two possible explanations.
One is that the exam was simply set at too hard a level.
Exam papers generally contain a range of questions of varying degrees of difficulty. Some are relatively straightforward and designed for candidates who merit a C grade pass - others are more demanding and designed for the most able.
Did an unduly difficult or badly set paper get through the SQA's quality assurance safeguards? Were candidates simply unprepared because the paper was unlike the one teachers had expected?
Some claim the paper was produced under an unusually tight deadline.
Another potential - but maybe more controversial - explanation touches on a more philosophical issue.
One aim of the changes to education in recent years under the banner of Curriculum for Excellence is to encourage youngsters to think for themselves and develop what might be termed a "deeper understanding" of a subject.
At Higher level, this sort of skill was always valued. In Maths it could mean that candidates had the knowledge and initiative to attempt to solve unfamiliar problems rather than just questions which may be similar to those in past papers or textbooks.
One senior figure in Scottish education was concerned the paper appeared to have been such a huge challenge for the most able candidates. To get an A grade candidates needed just 60%.
He said he had heard comments from teachers in good state and independent schools about what he called "the supposedly difficult" questions.
He said: "We have to ask if such questions are the kinds of things that we would expect someone competent to be able to answer at this level. I can't help concluding that they are and so that, whatever the explanation, if students can't do it then there is something wrong with the syllabus or with their capacity to exercise ingenuity.
"The most controversial feature is not really the drop in the threshold for a pass - though that is bad - but that an A could be obtained with as little as 60%.
"That is truly disturbing, since one would expect the most able students to be able to cope even with the supposedly 'too difficult' questions."
In the coming school year, only the new Highers will be on offer.
After what, frankly, has been a debacle with the new Higher Maths exam the challenge for the SQA is to ensure that teachers, students and parents can enjoy confidence in the altered qualification.