Clusters of High Abilities Variable by Birth Year?

Okay, I have no statistical evidence to back up my gut feeling but what do you all think?

It seems to me that some classes appear to have a larger cluster of high abilities kids as well as a greater number of extreme outlier kids. I stated birth year but that is really a proxy for class year although with most state cut-offs, the kids in each class already straddle two birth years, not even accounting for accelerated and red-shirted kids. I have noticed that my kids who are incoming 10th graders (born in 2003) have a lot more high ability peers than the class ahead of them and that there are also more extreme outlier kids in their class than the class ahead of them. This has been true across three different schools located in different regions of our very large district as well as observations at various state competitions. That was one reason why I did not grade skipped DS in elementary. I notice this same phenomenon in other classes as well. For example, the incoming 12th graders (as a class) seem to surpass the seniors (as a class) who just graduated.

Well I knew one teacher who claimed the classes varied according to the year of the Chinese calendar. It does seem that way but I suspect it is similar to some years being very boy heavy and some girl heavy.

Originally Posted by puffin

Well I knew one teacher who claimed the classes varied according to the year of the Chinese calendar.

This could explain why:

Chinese children born in the year of the dragon are more successful
by Isabella Steger
Quartz
August 30, 2017

Quote

No, children born in the year of the dragon are not born inherently superior.

Instead, the apparent success of these �dragon children� comes down to a lot of nurturing, according to two researchers at Louisiana State University (LSU) who studied the academic performance of people born in the year of the dragon in China. Due to the superstition that those born in that zodiac year will grow up to be more successful, places like China, Singapore, and Taiwan typically see a �baby boom� in those years. The last one fell in 2012.

In a working paper published this month by the US National Bureau of Economic Research, the researchers found that dragon children receive higher test scores in China�s national college examination and are more likely to go to university than people of a similar age born in other Chinese zodiac years. The researchers note that the findings come even as logically speaking, competition should be more intense for people born in the year of the dragon if there were more babies born in that year.

The kids in question wouldn't have known what Chinese year they were born in or been raised differently but i agree with the article. I think what she really meant was each class was diffent despite being roughly the same in all measurable ways.

If you count backwards X years, was there some change in curriculum or teaching standards or extra funding, etc., that happened when these kids were in primary school that could explain why one year group has thrived and others haven't?