After the Second World War the dominant form of ability grouping in United Kingdom primary schools was streaming (where children are allocated to classes ranked by ability). This normally began at age seven. It became increasingly unpopular because it led to low self-esteem and social alienation in pupils in the lower streams and the evidence of its positive effects on achievement was inconclusive.
These factors, combined with the demise of the 11-plus exam, and the new emphasis on equal opportunity, led most primary schools to establish mixed-ability classes which could be sub-divided into ability groups for specific subjects.
Over the past decade, the increasing national focus on raising performance has led the Department for Education and Employment, the Office for Standards in Education and individual schools to reconsider structured ability grouping.
Research suggests ability grouping is not a panacea (Hallam and Toutounji, 1996; Harlen and Malcolm, 1997; and Sukhnandan and Lee, 1998). However, in 1997, the Government White Paper Excellence in Schools indicated that setting (where children are placed in different classes for specific subjects) was "worth considering in primary schools".
A year later, chief inspector Chris Woodhead, in his annual report, argued that "setting can help teachers to plan work more precisely and select appropriate teaching methods".
A further OFSTED report, Setting in Primary Schools, published in 1998, presented research evidence, based on inspection reports and a questionnaire, which indicated that about 60 per cent of junior schools and half of primary schools adopted ability-setting for at least one subject in some year groups.