Emily Oster has commentary on the CDC milestone update that I find very compelling:
The last round of developmental milestones from the CDC focused more on what we would expect from the average child. This update is intended to capture something like: at least 75% of children at this age would meet this milestone.This means, then, that if a child is not meeting it, they are in the lower 25% in terms of that area. And this is the group we want to flag for possible early intervention. Prior to the update, the guidelines were closer to identifying the average — the 50th percentile. But, of course, moving from a milestone that identifies the 50th percentile of the distribution to one that identifies the 25th percentile will change the expectation.
Makes way more sense for the milestones to be 25th percentile if the goal is “have the milestones set that you SHOULD freak out if your child doesn’t meet them”, i.e. most children will meet them rather than only 50%.
Emily Oster has commentary on the CDC milestone update that I find very compelling:
Makes way more sense for the milestones to be 25th percentile if the goal is “have the milestones set that you SHOULD freak out if your child doesn’t meet them”, i.e. most children will meet them rather than only 50%.