Have you seen this?
http://www.nagc.org/index.aspx?id=2455I'd have a copy with me and highlight the important points.
If the Verbal Comprehension and Perceptual Reasoning Composite scores vary by less than 23 points, �the GAI may be calculated and interpreted as a reliable and valid estimate of a child�s global intellectual ability� (p. 128). Use of the GAI takes on special significance with the gifted. Verbal Comprehension and Perceptual Reasoning tasks are heavily loaded on abstract reasoning ability and are better indicators of giftedness than Working Memory (auditory memory that is manipulated) and Processing Speed (speed on paper-and-pencil tasks).
