I have a question about the Flynn effect. A friend had their child retested on the same test (sb5) by the same tester a number if years apart. The tester said not to bother, because the result would be the same, but school wanted retesting. The result was either identical or within 1-3 points (FSIQ) and similar pattern.
My question is - first round of testing was obviously closer to the point of norming than the second round of testing. Now theoretically what the tester said and what happened is exactly the intention of IQ test - that scores should be fairly stable (assuming no conditions that might cause change or instability). But if you test your 5yr old on the sb5 when it's is first released there should be no Flynn effect, your 5 yr is close in age to the norming cohort, when you test again at 15yrs old surely the Flynn effect should be reaching its peak effect for that test (your 15yr old is 10-15yrs younger than the norming sample), how does the Flynn effect theory balance against "stable over time on the same instrument"?
Note that my friend's child was not tested 10 years apart, the situation just got me thinking.
