ITV has a 23-minute video on the education system in Wales
In summary, Wales' decision to scrap standardised tests (so that children are never tested externally before their GCSEs) and to give lots of freedom to each school, instead of providing a more rigidly and uniformly structured curriculum, does not seem to have paid off, as Wales has the worst school results of the whole of the UK, and their scores keep getting worse.
Opinions, of course, vary.
I am not a fan of teaching to the test and I see how many schools resort to dirty tricks to boost their scores (eg "incentivising" certain pupils to leave, coming up with partially selective admission criteria to select more academic children, etc.).
But no tests at all risks creating chaos and a complete lack of accountability.
All I can say is I'm glad my kids do not go to school in Wales.