Someone made a specific decision to make 130 the cutoff; it has to be based on something (when I get a chance I want to research this for myself; it might be in the legislative history of the different state statutes). It may just be that represents the top 10% say for cognitive ability in any one class by grade level.
It is my understanding that on the "normal curve" of IQ distribution, 130 historically represents the upper limit of the 2nd standard deviation from the norm, the top 2% of the population, therefore identifies individuals with a relatively rare intellectual profile.
