Of course scientists are aware of medians. However if you look at PISA rankings, they use the mean scores not median.

You have way too much faith in rankings you see on the internet.

> Show me a better way to compare countries when it comes to reading skills.

Median scores, mean with standard deviation, box plots. All of those are better. None are great because comparing reading scores in different languages in a meaningful way is nearly impossible.

For example, Chinese children take much longer to develop their vocabulary than American students because of the way their language is written. Because of this you can't possibly construct a test that makes an accurate comparison between Chinese and American students.

You might as well try to make a test comparing how well American schools teach welding to how how well Chinese schools teach painting.

>You know there's studies ranking countries based on diversity right? You want me to Google them for you?

And only 1 of the countries that ranks higher than the US in diversity ranks higher than us on the PISA list.

https://en.wikipedia.org/wiki/List_of_countries_ranked_by_et...

The countries the US is unfavorably compared to nearly all appear near the bottom of that list.

It also doesn't take into account the amount of difference between cultures. For example, an African country where 20% of the people speak a different language from and don't intermarry with the dominant culture, but that have lived side by side with the dominant culture for hundreds of years will be ranked the same as a country where 20% of the people are immigrants from a country on the other side of the world.

The US has a far larger percentage of immigrants than any other country, and from far more countries.

Furthermore the US has far higher income inequality than most of the countries that outperform it.

>You just said you don't believe the study is relevant. So why do you care what it says.

It's not. I care that people are pushing PISA rankings as some kind of objective measurement of countries' education systems, and because of that politicians use them to try to push changes without understanding what the rankings actually show.

I can assure that in among academics in education PISA rankings are very controversial. Despite all your insistence about not being debatable it most definitely is.

Here's an example of some of the criticsm

--From the Times Educational Supplement

https://www.tes.com/news/school-news/breaking-news/long-read...
https://www.tes.com/news/tes-archive/tes-publication/pisa-ra...

"With greater power comes greater scrutiny. In 2013, TES revealed damning new allegations against Pisa from statistical and mathematical experts who said that what had become the world’s most influential education league tables were, in fact, “useless”, produced “meaningless” rankings and were compiled using techniques that were “utterly wrong”.

In response, the OECD admitted that “large variation in single country ranking positions is likely” because of the methods it used. For example, in 2009 the organisation said that the UK’s Pisa ranking out of a total of 74 countries was between 19th and 27th for reading, between 23rd and 31st for maths, and between 14th and 19th for science.

But this admission has made little difference to how rankings are reported in the media, and Pisa does not put the caveats centre stage. The resulting league tables are often taken as definitive statements on the quality of schools systems. And the stakes have become so high that a slip of a few positions caused by statistical variation might today spell the end of an education policy or even a minister’s career."

--From an open letter to the OECD by over 100 academics

https://www.theguardian.com/education/2014/may/06/oecd-pisa-...

"Critique #1: Whereas the explicit purpose of ranking countries by average test score is to allow for inferences about the quality of national educational systems, the ranking is misleading because the samples of students in different countries have different levels of family academic resources (FAR)."

"Critique #4: The OECD has repeatedly held up Shanghai students and the Shanghai educational system as a model for the rest of the world and as representative of China, yet the sample is not representative even of the Shanghai 15-year-old population and certainly not of China. In addition, Shanghai schools systematically exclude migrant youth. These issues should have kept Shanghai scores out of any OECD comparison group and raise serious questions about the OECD’s brand as an international testing agency."

"Develop alternatives to league tables: explore more meaningful and less easily sensationalised ways of reporting assessment outcomes. For example, comparing developing countries, where 15-year-olds are regularly drafted into child labour, with first-world countries makes neither educational nor political sense and opens OECD up for charges of educational colonialism.

--From a guardian article

https://www.theguardian.com/news/2013/dec/03/pisa-methodolog...

"From the outset, Pisa has been met with scepticism, criticism and even outrage, most of which has stemmed from the claim that the study's findings are arbitrary. One such voice was Dr Svein Sjøberg of the University of Oslo, who claimed that a small change in question choice or weightings could result in a big change in a country's overall rankings."

"The sheer breadth of Pisa has also raised questions about the comparability of results within it. Even those who accept it is fair to assess countries and economies alongside one another question some of the cultural factors that divide them. Joachim Wuttke, a teacher of computer science in Germany, is one such sceptic. Wuttke looked at which students failed to complete the test and which preferred to increase their speed – even at the risk of increasing their errors. He found significant differences in student behaviour that affected student performance:"

"At a more fundamental level, some have pointed to the difficulties of testing students in such a wide array of languages. If such a thing as a perfect translation exists (few would argue it does) it might still not be enough to control for students' differing interpretations of the same set of instructions."

"There is also a temptation to grab at averages from Pisa to understand the performance of a country. Doing so would obscure the vast differences that can occur regionally within a country – such an oversight can be particularly dangerous, say critics, for understanding the true academic opportunities available in a country."

"Meanwhile, countries such as Finland, a consistent top-performer in the Pisa league tables, has been accused of failing miserably on other international academic tests such as TIMSS. Why? Gabriel H Sahlgren, the author of a book on the dubiousness of the Finnish miracle claims it is “because its centralised curriculum has ignored certain concepts that are not tested in Pisa”."

https://www.washingtonpost.com/news/answer-sheet/wp/2015/04/...

http://nepc.colorado.edu/newsletter/2015/10/international-te...

https://www.uv.es/RELIEVE/v22n1/RELIEVEv22n1_M15eng.pdf