You raise excellent points.
What are your thoughts on this -
If more schools initiated utilization of the Iowa Acceleration Scale (IAS) as part of their policy/practice/process and therefore a grade-skip was not the result of strong parental advocacy... might the cohort of students who skipped one or more grades be more diverse... possibly leading to longitudinal study results which are more revealing?
On the other hand, those students for whom the IAS indicated a strong likelihood of success after a grade skip may be a good match for your described group of students with effective self-advocacy skills... those with a positive, resilient personality... a certain je ne sais quoi.
As you mentioned, rather than the grade skip being a cause of future success, the correlation of grade skip and future success may possibly be attributed to realizing that the endorsement to skip a grade may be responding to early detection of the same factors (skills and/or support) which later result in further success in advanced academics.
