Revealing the results of last year's pilot tests of the National Curriculum, Mr Patten said they were unacceptable and meant that the tests were essential to identify and help children with difficulties.
He quoted a recent survey of 16- year-old school-leavers which found that three out of 10 had reading ages of 14 and said: 'What more powerful case can there be for testing? If we do not check children's progress at key ages then we cannot know how they are getting on. We cannot give extra help to those who need it and parents will not be in the picture.'
The pilot tests in 1992, which were drastically modified for this year, involved 12,000 children at 102 schools. Three out of 10 only reached levels 3 to 4 in the National Curriculum, the equivalent of the average reading age for nine- to eleven-year-olds.
Mr Patten faces strong criticism from teachers over the way the tests for 14-year-olds, particularly in English, have been introduced. He conceded that schools' results should not be published this year. But he used his appearance before the Education Select Committee to warn teachers not to boycott the tests because this would damage children's education and harm their professional standing.
The National Union of Teachers has approved a boycott of the English tests in principle and the National Association of Schoolmasters Union of Women Teachers intends to boycott the tests in science, maths and technology as well. But, invited by Lady Olga Maitland, Tory MP for Sutton and Cheam, to say how he would ensure that children were protected from a boycott, Mr Patten declined to issue legal threats or spell out any policy for disciplining teachers.
This year teachers are being asked to grade children in four tiers before the tests and children will not be able to achieve a higher level than the one for which they have been entered. In Scotland the entire testing programme has been abandoned following boycotts by parents.Reuse content