Nearly 8,000 secondary pupils are due to sit the same English and maths tests as 600,000 11-year-olds as part of a pilot scheme to identify how to improve the performance of pupils in their early secondary years.
The new "progress" tests are being piloted in more than 150 secondary schools in 10 local authorities and could be offered to all lower achievers next year.
The tests are intended to give those pupils who failed to achieve the required standard (level 4) by the time they left their primary school at 11 the chance to prove they have caught up a year later.
The tests are the latest in a range of measures designed to help struggling 12-year-olds catch up with their classmates.
The pilot is being run by the Qualifications and Curriculum Authority quango.
Pupils who fail to reach the required standard at primar school can attend summer schools and will be expected to follow a new "catch-up" curriculum in English and maths during their first secondary year.
The pilot will use the tests to identify which strategies are the most successful at helping first-years' progress.
Participating schools will complete a questionnaire showing what booster activities their pupils have followed.
QCA officials will then be able to see which of the strategies used have the most impact on test performance.
Gail Cowmeadow, principal officer in QCA's assessment division, said: "The schools which volunteered to take part in the pilot have complete freedom to choose whether, or how, they inform pupils or parents about the tests. We will then try to evaluate what effect this had on pupil motivation and performance.
"We will also be asking to what extent their pupils were involved in summer school or special catch-up programmes and analysing the results to see which pupils have made the most progress."