Tables of examination results are seldom easy to understand, even for so-called experts.

The picture is often further obscured by the spin imparted to results by interested parties. So what do this year’s results actually tell us?

The flagship qualification of Scottish education is the Higher and this year’s results continue a pattern emerging since it was revamped in 2015 under the Curriculum for Excellence (CfE).

This suggests that Higher enrolments and successes have declined slowly, but steadily - in contrast with the period from 2000 to 2014 when Higher numbers improved.

It will be another year or two before a fuller picture is evident, but since no other initiatives have affected Higher since 2000, it seems reasonable to ask whether CfE and the new qualifications are linked to this pattern.

Higher and other late-school qualifications such as Advanced Higher are built on a platform generated by earlier schoolwork and there is still much uncertainty about the results of CfE and the results of this may be clearly seen in the 2018 National 3 to 5 results.

Overall attainment in Scotland at these levels is now down nearly 34 per cent on the last pre-CfE results in 2013 which is a highly significant decline which cannot be explained away as a result of the narrowed S4 curriculum adopted by many of Scotland’s secondary schools since 2013.

Several issues are hidden inside the global figures. The numbers of pupils attempting National 4 and, especially, National 3 have crashed since 2013.

Whereas over 60,000 pupils passed a National 3 course in 2013, only 16,138 did so in 2018.

It does not look as if this is a result of improved learning and teaching which is helping pupils to achieve National 4 or National 5 instead, with significant reductions in the numbers attempting these qualifications over the same period.

Indeed the latest figures show a reduction in entries at National 5 of 12,000 in this year alone.

This is significant because this is the first major drop since 2014 and would appear to suggest that the opportunities to study courses at National 5 have been reduced.

Because CfE encourages pupils to spend longer in the so-called broad general education in the first three years of secondary it means in many schools they do a smaller number of subjects once pupils reach S4.

This is a trend that seems to be growing with a greater number of schools now offering only six courses whereas previously the offer was more likely to be seven or eight.

There are more alarm bells in the pass rates for National 5. Part of the two per cent decline in the pass rate this year is likely to be because of the removal of teacher assessments which might have been more favourable to pupils in the past.

But there is another issue of pupils being put into the wrong level of qualification because of misplaced school or parental expectation.

One particularly worrying aspect of the National 5 numbers is that, whereas only one pupil in 11 failed such courses in 2013, it is now the case that one child in four fails.

Such a failure rate is doing an injustice to pupils and society in general.

In the case of higher ability pupils, the declines identified at National 5 and Higher represent a challenge to their ability to enter university, find high-value jobs or contribute to the economic progress of the country.

Dr Jim Scott is a former headteacher and lecturer at Dundee University