Cambridge Checkpoint was deliberately designed to be a very different sort of test to Key Stage 3 (KS3). Cambridge Checkpoint is a diagnostic test, designed to be used by teachers as a tool to help them to focus and improve their teaching. KS3 is a summative test designed to assess students' (and to some extent teachers') performance. The scores on the Cambridge Checkpoint scales are 0.0 to 6.0 whereas the KS3 SATs levels are commonly 4_7.
There may well be a strong correlation between Cambridge Checkpoint scores and KS3 levels, in the sense that students who perform well on one test are likely to score well on the other as well. However, as students do not in practice take both tests, it is not possible to gather evidence to make any claims of equivalence between Cambridge Checkpoint and KS3 levels.
We have reviewed the curriculum frameworks for Cambridge Secondary 1 alongside the National Curriculum for England, which can be found on our website here.