Few children entered Year 3 with below-average KS1 scores. Children entering on Level 2C who make average progress have their points rounded up, resulting in a positive effect on the score.
Several children had KS1 scores too high for their ability. They were never likely to meet their projected KS2 score and inevitably had a negative effect.
We were in the first year of expanding from two to three-form entry, creating many extra places in Year 6. Many late entrants had made insufficient progress since KS1, and contributed substantially to our negative VA score.
One statemented child was unable to take the tests and was awarded arbitrary points. The negative effect of this one child was considerable.
When Ofsted arrived it was obsessed with the new score. Inspectors refused to acknowledge any mitigating circumstances. The more we tried to explain, the more adamant they became that we were making excuses.
This completely new statistic was regarded as an infallible measure of our effectiveness. The school was judged to have serious weaknesses. Even the full support of the LEA, advising that Ofsted was mistaken, fell on deaf ears.
After two stressful years, a further inspection has found us, once again, to be a good school with no significant weaknesses. The message was: If your VA is positive, then teaching must be good. If your VA is negative, then teaching can't be good. Surely, if this is such a reliable method, we could abolish inspections, and simply make an annual announcement of the statistics.