A SLUMP in school standards has been blamed on the controversial practice of teaching pupils different qualifications in the same class.

A leading academic said so-called multi-course teaching was one of the reasons for the decline highlighted in a prominent international education survey – particularly in science.

In December, the Programme for International Student Assessment (Pisa) concluded that Scotland’s performance was now “average” compared to other developed countries in science, as well as in maths and reading.

In 2000, when Scotland first took part in the OECD survey of 15-year-olds, its performance in all three disciplines was above average.

Multi-course teaching has become more common as a result of teacher shortages because schools can timetable pupils studying the same subjects at different levels – such as National 5 or Higher – in the same class.

David Cole-Hamilton, Emeritus Professor of Chemistry at St Andrews University and a member of the Royal Society of Edinburgh’s education committee, said multi-course teaching should only be used where absolutely necessary.

Writing in The Herald, he said: “A major drop in attainment is very unlikely to arise because of a sudden change in pupils. Nor is it the hardworking, very talented and highly motivated teachers, who do their very best for their pupils. In my view, a prominent issue concerns multi-course teaching, which involves teaching two or more sets of pupils studying for different qualifications by the same teacher at the same time.”

Mr Cole-Hamilton said such teaching worked in rural schools with small numbers of pupils where significant individual help was possible, but in other schools teachers were unable to meet the needs of their learners.

He added: “The difficulties are especially stark in science because safety dictates that a teacher’s full attention must be given to those carrying out practical work. In addition, the content and learning objectives for units in National 4, National 5 and Higher are quite different.

“I am certain that sorting out problems by reducing the assessment load ... and having multi-course teaching where it is absolutely essential will allow for excellent courses which will again make Scottish education the envy of the world.”

A survey by the Scottish Secondary Teachers’ Association (SSTA) in 2015 found 47 per cent of members were teaching classes containing pupils aiming at two different qualifications and a quarter had pupils studying three.

A separate study this year by the Royal Society of Chemistry Education Division in Scotland found 73 per cent of National 5 chemistry classes had pupils studying for other qualifications and 21 per cent of Higher courses being taught were multi-course.

Asked how well they felt able to support pupils in multi-course classes, 70 per cent of teachers in National 4 and National 5 classes responded either “not at all” or “not very well”.

A spokesman for the SSTA said: “We are becoming increasingly alarmed at the complacency in some local authority and government circles that believe there is not a teacher shortage. Teachers are in many cases timetabled up to the maximum 22.5 hours and, in some instances, are having to take two National qualification classes at the same time.”

Larry Flanagan, general secretary of the Educational Institute of Scotland, said multi-level classes were a concern, especially in “content heavy” subjects such as the sciences.

He said: “The problems of bi-level and multi-level classes have certainly multiplied under the new qualifications. In effect you have two classes being run in the same room to the detriment of both groups of pupils. It can be less of an issue in some subjects such as English where differentiation is often by performance, but even here teachers are expressing concerns about trying to shoehorn too many courses into single class sets.”