Cameron can't favour both choice and setting

In attempting to put the grammar school row to rest, David Cameron is advocating an increase in setting and streaming in comprehensive schools. But what are setting and streaming? Parents may be confused by the terminology, not least because Mr Cameron seems so too.

Streaming is when children are organised into classes according to their general ability. But most children are better at some things than others, so the A stream, for example, will contain some children who are very good at English but poor at mathematics, and vice-versa. Streaming is the antithesis of personalised learning. In other words, you can't be in favour of both streaming and personalised learning. Which mast are your colours flying from, Mr Cameron?

Setting, by contrast, puts pupils in groups by ability in each subject, thus attempting to overcome the disadvantage of streaming. While some children will be in the top or bottom set for all their subjects, the majority vary in ability between subjects and are placed in different sets.

Mixed ability is what Mr Cameron doesn't like. These classes comprise children of all abilities and, when well-taught, cater to the needs of children of all levels of ability, using a range of resources and teaching techniques. This is the norm in primary schools, where it is uncontroversial. Those who want to denigrate secondary schools, however, castigate them for all the mixed-ability teaching that is alleged to take place. Ofsted has found that mixed-ability teaching increased more than 10 per cent between 2002-03 and 2005-06. But because of the new inspection system, this is not comparing like with like.

The reality is that, in secondary schools, the majority of lessons in English, mathematics, science and modern foreign languages is set by ability. According to government statistics, 75 per cent of mathematics lessons are in sets, 63 per cent in science. Both figures increased 10 per cent between 1997 and 2002 and fell by the same amount by 2005. This rise and fall mirrors the fall and rise in choice of courses for secondary school students, especially 14- and 15-year-olds.

A common practice is for secondary schools to place 11-year-olds in mixed-ability groups while they find their feet in the new school. At some point in the first half of the year, many schools put the children into sets for mathematics and modern languages, the two "progressive" subjects – i.e. those in which knowledge in one lesson most depends on having understood the previous lessons.

Twelve- and 13-year-olds are generally in sets for English, mathematics and modern languages, and often also for science, history and geography. Very rarely are children in ability sets for physical education, religious education, IT, art, music, design and technology or personal, social and health education. I have never heard a coherent argument for putting children in sets for these subjects. "Jack is in the top set for personal development" is not something that parents are likely to want to hear, still less if he is in the bottom set.

Arrangements are rather different for 14- and 15-year-olds, as they have a choice of (usually four) subjects, their "options". In most schools, these include history, geography, modern languages, art, music, drama, business, technology, and vocational subjects.

It is impossible to have both choice and setting for 14-year-olds. So, if you believe in choice, as all political parties do, and this belief extends to choosing subjects at age 14 to study for GCSEs, you cannot have setting for the 40 per cent of the week during which this age group is studying its option subjects. English, mathematics and science, which take up nearly 50 per cent of the week for 14- and 15-year-olds, are almost always taught in sets. (Sixth forms are usually excluded from the debate, but it is noteworthy that they are virtually never taught in ability sets.)

To sum up all the statistics, 11- to 16-year-olds are in sets for around 45 per cent of the time. If Mr Cameron wants to increase this proportion, he needs to be clear whether he is suggesting less choice for 14- and 15-year-olds, or more personal and social education, physical education, art and music taught in sets. Or perhaps he is suggesting setting for 11-year-olds, as soon as they arrive in secondary schools?

Even if the statistics support Mr Cameron's argument, which they don't, the task of deciding how to organise the school timetable is one for head teachers, not politicians. When politicians start meddling in the internal organisation of schools, they usually get it wrong. Their job is to hold schools to account for outcomes, not processes. It is ironic that political parties that preach greater autonomy for head teachers should seek to direct how they organise their classes.

The writer is general secretary of the Association of School and College Leaders