I think red shirting does muddy the water for gifted kids
I completely agree with this idea--even amongst kids who are actually gifted, I think that this can be confusing.
Our DD was one of 4 kids in her K class who were considered an academic cluster. However, she was nearly a full year younger than two of those kids. This was not due to redshirting, just to late summer/early fall birthdays. Still, I have come to believe that performing/learning at the same level/rate as kids almost a year older is significant at that age. As kids age and share instructional experiences, perhaps making within grade comparisons becomes more valid--regardless of age, classmates would have at least the same number of instructional years under their belt. However, when they're just starting school, I think that the age differences are more telling--especially when the kids you are compared to are already leaps and bounds beyond the rest of the class.
DD's ability to keep up with, and in some areas consistently exceed the benchmarks set by the peers in her cluster, was one of the significant "aha" factors in our starting to think about giftedness. I realized that if she had been born five weeks later (thereby starting kindergarten a year later), she would certainly have been *vastly* ahead of even her strongest grade level peers.
I don't at all regret starting her on time. I do think though, that being clustered with "same age" peers who were really a year older, obscured her school's sense of her as a learner. Certainly it made it easier for them to brush off our concerns.
That said, I think the solution is probably not about the question of when to start children in school, it's about the question of improving identification tools/protocols. It seems to me that while, achievment measures are most appropriately based on grade level (post kindergarten/first grade), aptitude types of measures need to be age based and more widely administered and used. That would make it more obvious when a child might need a more compacted curriculum and/or other types of interventions.
