IQ Trend Analysis:

The self-reported IQ results on these surveys have been, to use Yvain's wording, "ridiculed" because they'd mean that the average LessWronger is gifted. Various other questions were added to the survey this time which gives us things to check against, and the results of these other questions have made the IQ figures more believable.

Summary:

LessWrong has lost IQ points on the self-reported scores every year for a total of 7.18 IQ points in 3.7 years or about 2 points per year. If LessWrong began with 145.88 IQ points in May 2009, then LessWrong has lost over half of it's giftedness (using IQ 132 as the definition, explained below).

The self-reported figures for each year:

IQ on 03/12/2009: 145.88

IQ on 00/00/2010: Unknown*

IQ on 12/05/2011: 140

IQ on 11/29/2012: 138.7

IQ points lost each year:

2.94 IQ point drop for 2010 (Estimated*)

2.94 IQ point drop for 2011 (Estimated*)

1.30 IQ point drop for 2012

Analysis:

Average IQ points lost per year: 1.94

Total IQ points lost: 7.18 in 3.7 years

Total IQ points LessWrong had above the gifted line: 13.88 (145.88 - 132*)

Percent less giftedness on the last survey result: 52% (7.18 / 13.88)

Footnotes:

* Unknown 2010 figures: There was no 2010 survey. The first line of the 2011 survey proposition mentions that.

* Estimated IQ point drops for 2010 and 2011: I divided the 2011 IQ drop by 2 and distributed it across 10/11.

* IQ 132 significance: IQ 132 is the top 2% (This may vary a little bit from one IQ test to another) which would qualify one as gifted by every IQ-based definition I know of. It is also (roughly) Mensa's entrance requirement (depending on the test) though Mensa does not dictate the legal or psychologist's definitions of giftedness. They are a club, not a developmental psychology authority.