| This table was originally published on the GT-Families mailing list as the Secret Weapon.
It got that name because it is guarded closely by the special education folks in the poster's
district, not because the information it provides is anything resembling groundbreaking.
This chart is nothing more than the result of calculating a range of values from the definition of IQ which
calculates IQ as the ratio of mental age (MA) to chronological age (CA) For
this reason, the original source of the chart (which has been lost to the ages) is not relevant.
When the simplicity of the calculation is considered, several weaknesses of this chart as diagnostic instrument
for the purpose of determining appropriate placement are revealed.
The chart takes no account of individual differences in
- school curriculum
- IQ measurement instruments (see our GT Testing Page)
- length of instructional year
- social factors
Even so, this chart can be a powerful tool for advocacy, in that it dramatically
points out how the standard pace of instruction "aimed towards the middle" of chronological peers
becomes more and more inappropriate as a child's school career progresses.
It also can help to answer the question "What difference does it make whether
there are ceiling effects on the testing instrument...we know s/he's gifted!"
The chart demonstrates how a gifted program targeted to serve
children with IQ's of 130-145 is entirely inadequate for the highly or exceptionally
gifted child of IQ 145+ and an order of magnitude inappropriate for exceptionally gifted children
of 160+.
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