I posted the other day about the heritability of reading ability. Another new study discussed in Science Daily says that a kid's reading ability in 7th grade is closely related to where they lived in kindergarten, in particular the level of poverty in their childhood neighborhood.
Being behind early means being farther behind later. Being behind builds. This means that when we fail to help a kid by kindergarten, that kid may be lost. It's up to us to save the world, or at least the part of it that can be saved by high-quality child care.