Gifted Issues Discussion homepage Forums Identification, Testing & Assessment Test results

So... We got my DS's testing done and the result are back. We tested for consideration of a skip to first grade next year. The school psychologist and the principle agree that he is a great candidate for a skip. So that is nice to be able to move forward with that. I'm about 99% sure that we want to skip, although there are still some lingering doubts. Anyways, on to the test scores. He did both WJIII for achievement and cognitive.
The first day he did the cognitive:
GIA: 125
Verbal ability: 120
Thinking ability: 140
Cog efficiency: 108
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Verbal comprehension: 120
Visual- auditorial learning: 119
Spatial relations: 125
Sound blending: 161
Concept formation: 130
Visual matching: 108
Numbers reversed: 106

Then he took the achievement test the next day:
Brief achievement: 162
Broad math: 155
Brief reading: 171
Basic reading skills: 166
Reading comp: 142
Brief math: 153
Math calc skills: 140
Academic skills: 164

Is it common for there to be a huge difference between the achievement scores and the cognitive? Do you guys think that given his young age that the cognitive portion could be off? The school psychologist is also an intern and has only been doing this for 2 years, mostly testing under achieving students. I don't feel the need for his iq score to be higher. As it is, it serves its purpose. I'm just not sure I trust it entirely. What are your thoughts

I've been thinking, and have more questions.
First, am I right that based off his achievement scores he would qualify for DYS?
Then, if his iq score really is his true iq score (which I believe falls in the MG range) would this mean that his achievement and development would likely level off to meet the iq? I only want to do a skip if we can also still do the gifted program when it comes available in 3rd grade.
My DS is 5.3 yrs old... This big of a decision is so hard to make...