That would be global, the OG article is focused on the USA. America does not have a good track record of making sure it's public schools are well funded and being held to a standard.

https://futurism.com/neoscope/human-intelligence-declining-trends

I was curious about the PISA test mentioned in that article and also found this.

https://www.educationnext.org/pisa-mission-failure-with-so-much-evidence-student-testing-why-do-education-systems-struggle/