I'm a high school teacher and I can really see this compounding problems at our end.
We see so many kids who really can't cope and aren't ready for high school yet are forced to move on to year 7 regardless. A lot of my students in year 7 could really have done with an extra year before coming to high school - whether that means being held back or whether they should have waited a year before starting primary school I just don't know.
I started when I was 4 (I turned 5 in February) and I did brilliantly academically, but socially I didn't do so well. I was dux of my school, but had very few friends. My sister on the other hand, started when she was 4 (turned 5 in May) and was held back a year in primary school. She did much better than me socially, but her academic performance was very sub-standard. She's just not an academic person where I was.
What works for one child does not necessarily work for all, while the advantages of having uniformity across the nation are immense, I really think they should head towards a higher minimum age. Or perhaps assess each studen'ts readyness for school on an individual basis.
I think I'm going to be a little controversial here - but I believe that something like the American system where a student is held back if they don't meet outcomes would certainly be a good idea. It minimises the frustration of pushing kids through the system where at the end of year 10 they can still barely read.
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