I just want to remind people again that Finnish pupils have no formal testing or ranking before the age of 18, yet regularly outperform the rest of the world.
But they have the advantage of having one of the world's simplest spelling systems. It uses just 38 totally reliable spellings for its 38 speech sounds. This enables pupils to learn to read and write very easily and exceptionally fast, and to move on to other learning shortly after starting school.
English spelling lies at the opposite end of the range. The 44 English sounds are spelt with 205 graphemes, many of which are totally unpredictable (leave, sleeve, believe, ravine, even...). Worse still, 69 spellings have more than one pronunciation (treat, great, threat) and make learning to read and exceptionally difficult and time-consuming, and much harder to teach too, and delay access to other learning.
When something is difficult and takes a long time to learn, there is far more scope for falling behind, and careful monitoring of progress is more important, but only if this leads to the provision of appropriate support where needed.
Teachers usually know which children are not keeping up but have difficulty getting them the help they need. It would be much better to spend money on that instead of on more, or more rigorous, testing.
The best solution of all would be to make English spelling more learner-friendly.