Even if we take a face value the assertion that a 1200 one time check raised so many people out of poverty, it seems incredibly difficult to believe that single check for that single time was enough to change this "average poverty" value from 2x the other countries being referenced to not only less than half of that value, but also below 2 of the 3 comparative counties in the same time period AND 60% of the value in 1990 where the US was supposedly running equal with the comparative countries. Looking at the article graphs, none of the comparative countries see even a blip in their trends during the same time period. For that to make sense, especially in light of the rest of the article, it seems like a handful of things would have to be true:

1) That all of the effects of America's wealth inequality on American poverty could be made up for simply by giving everyone a thousand dollars a year. Not even UBI proponents are that optimistic.

2) That nothing any of the 3 comparative countries did or did not do during a massive global pandemic did anything to alter the relative poverty levels of their populations in the slightest

3) That the major economic crashes and recessions over the last few decades have actually improved American average poverty (notice that the US rate dips for the beginnings of the dot com crash, 9/11 and the 2008 financial crisis, despite none of those coming with government stimulus checks.

This measurement might be have something interesting to say, but I'm not sure it's saying what is being claimed. It feels more like they've found a more volatile measure of the US economy and stock market than of poverty.