How stupid are you? You have no idea!

He explains it so clearly, though somewhat misses the flip side where those who are intelligent have a tendency to doubt how smart they really are.

Although apparently people at the 70th percentile have it nailed! (Although, how would they know they're at the 70th percentile?)

@Steve--

It's very simple. If you think you scored a 70, you did!

Of course, the really scary part is how really stupid the really stupid really are... That, along with how often we put them in control of things because they sound so confident.

George Carlin — 'Think of how stupid the average person is, and realize half of them are stupider than that.'

But, I think stupidity vs intelligence is not the correct metric.

At one end, it is lack of knowledge/skill, and sometimes total unwillingness to acquire it. Those are truly D-K-afflictees.
After all, there are lots of people with technical PhDs who think they are smarter than climate scientists and know AGW i wrong. There are often combinations of reasons.

But such folks rarely ask questions of experts in public, attend seminars by experts or go to AGU or EGU. A perfect example is the Stockkholm Initiative, where the latest post extols Andrew Montford, GWPF, and then Ian Plimer's book ... to help students.
See backgrounds, 4 are Emeritus professors.
(All these are in Swedish, so use Chrome to browse, as the built-in translation works smoother there.)

They cannot have low IQs, but most seem to think Murry Salby is right, Pehr Bjornbom has done many posts on that. Lennart Bengtsson (a real climate scientist) shows up, says why not, and they argue with him, then return to discussing the merits of Salby's pseudoscience. Their idea of checking things is to look them up in Wikipedia or reading Jo Nova.

While D+K say that it is possible to learn, I rarely see any evidence of that in the blogosphere, so that I've long ago established a policy of KILLFILE for anyone who clearly establishes an intense D-K pattern. (Meaning, don't bother reading, and *never* engage with them.)

But, there was one over at ATTP that was too amusing not to mention in a D-K thread.

"Michael 2 says:
September 29, 2014 at 4:23 pm
John Mashey says “a useful skill set is that of assessing expertise, something the Dunning-Kruger-afflicted especially lack.”
Nice demonstration of the Dunning-Kruger phenomenon :-)

http://en.wikipedia.org/wiki/Dunning%E2%80%93Kruger_effect
People are not “afflicted” with Dunning-Kruger. It is a word that describes both expert and inexpert persons; experts tend to deprecate their own expertise while unskilled persons tend to exaggerate their expertise.
The reason is simple — the more you learn the more you realize the magnitude of what *could* be learned but has not yet been learned.
A person just starting out in computer programming creates “hello, world!” and feels creative and powerful. That is good, because it is a long road ahead of him or her.
Your demonstration reveals that you know the words “Dunning-Kruger” but clearly do not understand the meaning thereof or you would not be carelessly calling it an “affliction”.'

Now, it turns out this was amusing enough to mention here for 3 reasons.
1) "Afflicted" has wider uses than pain, such as Afflicted means "impaired" or "stricken" and usually refers to a person who is mentally or physically unfit, or has been grievously affected by disease. If D-K prevents one from learning from those who know more, it is a serious learning impairment.

2) The "Hello world" example is especially funny. I'm not sure if it is supposed to impress ... but it happens that was introduced (in C, from where it spread) by a friend named Brian Kernighan, Bell Labs TM-74-1273-12, May 6, 1974 in "Programming in C: A Tutorial," I still have a copy and am probably one of those who commented on the draft, since I was already using C. Brian and I later wrote a few papers together.

3a) Some people look up D-K in Wikipedia.
3b) Fewer people also go read the original paper.
3c) And of course, a very few of us engage the researchers.
I have exchanged half a dozen or so emails with David Dunning, as I had some questions beyond the paper, and he was interested in D-K effects on climate blogs.
I sent him examples (some of which made him cringe) also reviewed a paper he sent for comments.
Wikipedia is OK, but conversations with experts is a lot more useful.

So,this was indeed a good demo of D-K, perhaps a bit recursively :-)

"Stupid is as stupid does."
--Forrest Gump

Doug, You're assuming that the mean equals the median. With regards to intelligence, I don't think that's the case... (There's a skew to the distribution.)

Correction: George Carlin was implying that. (Sorry!)

Rob, et al: Go rent the film "Idiocrasy" for an idea of how bad it can be -- and one cheeky theory of how it can get there.

(Not an A-List film by any means, but it has its moments of hilarity, so worth a watch. You'll swear you can see some of the changes in society since the film was made... Some web sites enumerate the "predicted changes" that they show already HAVE happened.)

John Mashey: M2 stated that he spent some 14 years getting certified to configure Cisco routing equipment. (So... 2 year diploma and a lot of hard work?) But at least he's certified.

Idiocracy has its moments - and I love Maya - but I wouldn't count on the science standing up to rigorous examination.