Originally Posted by MVMom
...advice I was given for years that emphasized the importance of kids staying with their age peers in school no matter what. Why do some early childhood educators believe this? Is there any basis for this strong bias toward age-grouping regardless of outlier ability levels? We've seen the gap between my child and his age peers widen dramatically over time. Did his preschool teachers believe that the gap would get smaller?
There is a common belief that kids even out by 3rd grade. While this is a myth, it may fed by facts such as:
- IQ scores being more stable at about 8 years old than they tend to be at younger ages...
- Some gifted kids may begin to zone out and underachieve if they've not had their learning needs met (have not been appropriately challenged)...
- More gifted kids may "dumb down" in order to blend in with same-age peers...
- Other gifted kids may have difficulty compensating for undiagnosed learning disabilities as academics become more demanding...
- Some pushed, hot-housed, or tiger-parented children may no longer exhibit relatively higher achievement as compared with same-age peers, once these peers become exposed to academics which allow them to achieve at the same high level.

This article by Carol Bainbridge discusses various facets of whether kids even out by 3rd grade.