All teachers of Year 6 children, or “top juniors” as they are still called in some circles, have recently gone through an anxious wait for the postman. The wait promoted more excitement than a childhood Christmas or the will of great aunt Maude. When the packages were finally dumped on the office floor, we took them off to a quiet corner like wild animals with their prey. The packaging was ripped open and the results of the Sats (recently renamed national tests) revealed.

Calculators, previous performance charts and national ratings are now essential for teachers wanting to assess their school’s Sats performance. Is the overall percentage of level 4s and 5s better than last year, equivalent to the national average, superior to other schools with similar benchmarks? It’s all so fascinating and all so pointless in its present form. Yet school reputations, and now threshold payments, rest on these dubious statistics.

So why are Sats so pointless? Well, mainly because they simply miss the point. Sats were introduced to measure the overall performance of a school through the achievements of its pupils. Now they are clearly being used as a tool to vindicate costly government initiatives.

Two years ago, literacy hour was introduced in our schools. Assuming it takes two years to get such an undertaking working efficiently, we should now be seeing the benefits in Sats results, and - surprise surprise - they have improved.

Children who I confidently predicted would be solid 3s have come out as solid 4s and those whom I expected to be solid 4s have gained a 5. For some children, I was so confident of their final level that I wuld have given up my right to threshold had I been wrong. But apparently I was wrong. They were much better than I had expected.

Conversely, the results of numeracy are generally worse than expected.

Consider the facts.

Numeracy hour only started this year. Schools are still fine-tuning their numeracy plans, so the results are unlikely to improve considerably until next year.

My school’s numeracy results are about as disappointing as the literacy ones are pleasing.If I had been a betting man, I would have lost heavily.

What has clearly happened is that numeracy levels have been kept artificially low to make them look good next year when numeracy hour is functioning efficiently, vindicating the Government’s initiatives.

The discrepancies are so apparent this year that a colleague has worked out that it was 10 per cent harder to achieve a level 4 in numeracy than last year. Don’t ask me how this was done, but she is convinced that her study was genuine. What is clear, however, is that Sats provide a convenient opportunity to endorse the worth of their policies.

Sats have never been popular among the teaching profession. There is growing evidence that they are labour intensive, inaccurate, open to abuse, and easily manipulated to make governments look good. The only effective form of assessment is by the teacher, who knows what a child can achieve over a year and not over three hours on a hot May morning, when a wasp is being a nuisance and grandma is in hospital, and the guinea pig has just died. That is no way to make sweeping assumptions about the health of education in this country.

Steve Devrell is a teacher in Solihull, West Midlands.