It is a national test that is taken be all the children in the country at the end of the Key Stage.
Pupils are given a level of attainment (ability) in English, Maths and Science at the end of Key Stage 1 and 2.
At Key Stage 1 there are tests that teachers use but they are informal.
At KS2 the children are tested on the following:
In Key Stage 1 the children are tested on their Maths, Reading, Writing and Science.
These assessments take place in an environment the children are familiar with and the children are tested by their teacher.
The assessments are informal and the children are assessed either one to one or in small groups.
In Year 1 all children are assessed on their understanding of Phonics. They are assessed one to one by their class teacher.