The scaled scores are not set until after the SATS tests have been completed.
A pupil’s scaled score is based on their raw score. The raw score is the total number of marks a pupil scores in a test, based on the number of questions they answered correctly.
We develop tests each year to the same specification, but because the questions must be different, the difficulty of tests may vary slightly each year. This means we need to convert the raw scores pupils get in the tests into a scaled score, to ensure we can make accurate comparisons of pupil performance over time. Every scaled score will represent the same level of attainment for a pupil each year, so a pupil who scores 103, for example, in 2016 will have demonstrated the same attainment as a pupil who scores 103 in 2017.
A scaled score of 100 will always represent the expected standard on the test. Pupils scoring 100 or more will have met the expected standard on the test.
So basically, until the children have set the tests and discovered how hard they are, scaled scores can't be set!