Pupils largely behave well, as previous research has shown, but social inclusion policies, an inappropriate curriculum and lack of consistent support from management contribute to poor behaviour among others. Teachers believe a clear set of national guidelines on dealing with disruption would make their job easier.
The findings emerge from a questionnaire sent to the homes of 5,000 teachers, focus groups and individual responses. But only 704 teachers - 14 per cent of the sample - bothered to reply, a "disappointing" return, according to council leaders.
The GTC initiated its study after being inundated with correspondence on indiscipline and its effects on morale and set up a working group to follow it through.
The overwhelming demand is for smaller classes. As one teacher put it:
"Certain pupils misbehave badly in mainstream classes. In smaller classes, they have less opportunity to do so." Pupils would receive more individual attention and staff would get to know them better.
Mixed-ability classes are not viewed positively by teachers and some pointed out that even small classes can require mixed-ability groups. One summed up: "At the moment I have a small composite P6-7 of 18 pupils but ability from level A in writing to level E."
An alternative view was that pupils learn from each other in mixed groupings and act on positive role models. Setting or streaming led to lower-ability pupils seeing themselves as inferior, which in turn led to more disruption. But this was countered by others who believe mixed-ability lessons lead to "massive preparation, planning and teaching. Also to stress."
Almost one in three teachers (30 per cent) listed mixed-ability classes as the most negative factor in indiscipline, with more in secondaries taking that view. The majority of teachers in primary and secondary say setting or streaming has a positive effect on behaviour. As one put it: "More able children can be stretched. Less able get more support."
Another commented: "Setting can concentrate indiscipline in lower sets but this may mean that other sets can make more progress. It can polarise behaviour and learning. Mixed-ability may not cater well for children at each end of the ability spectrum but allows children greater scope to learn from each other."
The nature of the curriculum is also an issue for many teachers who back greater flexibility. As the GTC states: "The curriculum is seen by a number of both primary and secondary teachers as being too rigid and too overcrowded. Primary respondents see 5-14 as being too broad and neither allowing teachers the time to cover it all as well as meeting basic needs nor allowing a child-centred education to take place.
"Secondary teachers comment on the irrelevance of certain courses which are over-academic and thus not of practical or vocational use to pupils and their immediate future."
Social inclusion policies take a hammering from teachers, with 70 per cent reporting they have a negative or very negative effect on behaviour. One teacher said: "Social inclusion is fine if we are talking about physical disabilities. There has been a serious deterioration of general behaviour in classroom with children with ADHD (attention deficit hyperactivity disorder) complaints."
Teachers often see inclusion as involving pupils with behavioural difficulties who should be in special schools. Many complain about a lack of training and support, while 70 per cent regard exclusion as a positive factor in pupil behaviour. "It allows classes to get on with the business of learning. Takes some stress away from teacher," one response said.
Poor management by senior school staff is a further dimension. One teacher commented: "Weak. Nice people but give in to parents too often. Have attitude that there are no good teachers in the school."
Consistency and whole-school positive discipline policies are seen by teachers as important in creating a strong ethos.
Discipline in Scottish Schools: A Survey of Teachers' Views is on the GTCS website.