The USSR was far less corrupt than the previous Tsarist system and the future Capitalist Russian Federation. Additionally, there was far lower wealth disparity in the USSR than in Tsarist Russia or the Capitalist Russian Federation, as shown in this figure:
how could this ever be used to treat the validity of communism?
Because life expectancy doubled, the USSR went from pre-industrial feudalism to space in half a century, literacy rates skyrocketed, home ownership skyrocketed, healthcare and university-level education were free, and the USSR had more vacation days than the US, with lower retirement ages. Read Blackshirts and Reds if you don't believe me.
Personally I do not believe it can ever exist. Humans wouldn't allow it thanks to human nature.
This is idealism, and contradicts history and science. What is considered "Human Nature" changes alongside technological development and Mode of Production.
You still cannot compare testing the validity of communism to testing the validity of climate change. Which is the whole reason for my initial comment.
What, precisely, do you contest in my comment? AES states have largely made great strides in improving conditions for the Working Class. This is provable with metrics and data. Additionally, you didn't respond to the bit on Human Nature, which I hope means you changed your mind but somehow I doubt that.
It doesn't matter... you cannot test communism(or any form of government) performed by a nation of millions of humans which is subjective in any way as clearly as you can test climate change because it is not subjective.