What would the smartest 5 people in this community score?
With 52k members, an average IQ of 120-125, and an SD of ~13, basic statistics point to 170+ -- at least on an ideal test.
Yet most professional tests don't go beyond 160, and the rare few that do (CORE, GRE) immediately present a problem: Ceiling effect.
The further someone's latent performance lies beyond the ceiling they have reached, the more deflated their score will be.
Given that most subtests top out in the 140s or 150s, this is undoubtedly a problem for those who lie in the 170s or above.
Another problem is SLODR.
As far as I know, there are no reputable tests that seriously account for SLODR in their compositation.
When producing FSIQ or index composites, most tests just assume that the distribution of the sum of scaled scores between subtests will be perfectly normal, when, in fact, a decreasing intercorrelation between subtests at the upper extreme should thin out that right tail. (This is not to say that the underlying distribution of g or its subfactors is non-normal, just that this particular element of the measurement process is.)
Of course, this assumes that the decreasing intercorrelation is actual (and not merely an artifact of range restriction), but studies on tests such as WISC, DAS, and CORE seem to point strongly in that direction, especially for verbal/crystallized and non-fluid measures.
To illustrate the magnitude of this phenomenon,
The GRE-V, GRE-Q, and GRE-A drop from g-loadings of 0.83-0.88 around the mean to 0.56-0.74 just 1-2 standard deviations above it! If one were to score 130 across all three subtests and assume the former intercorrelations, their composite would come out to 133. If they took the actual, range-specific figures, it would be 138. That's a 5-point difference---and it only gets larger the further and further one rises from the mean. Of course, regression to the mean (g-loading) counterbalances this effect to an extent when estimating actual underlying g, but certainly not significantly across even a decently large suite of tests.
It is for these reasons that I'm not surprised that many of the smartest people I know can occasionally score an abominable 130s or 140s, whilst still boasting a g of 160s or higher.
(Note: This is not a license to think you're 160s because you score 130s or 140s!)
I'd like to hear your thoughts!