Thanks for stating just how much of a statistical minefield this is. The reference does a great job showing just how wrong the DK studies are. Unfortunately, most people have already made up their minds and are happy to link conflicting blog posts as evidence.
The DK studies are not wrong, they are misinterpreted by people who don't know what they're talking about (e.g. what tge DK effect actually is), like this blogger.
"People have worse self assessment ability as their real ability declines" would be a valid interpretation of the DK data and notably would NOT be a valid conclusion from the random data in the blog post.
