This is a pretty good summary of the research on daycare effectiveness. It is a Much More Than You Wanted To Know-style post from a science blogger criticalscience who has some interesting posts on Medium.
TL;DR:
Adverse effects on children younger than three years old.
The effect is worse the younger the children are.
The effect is stronger for longer hours.
The effect is weakerCORRECTION: worse for children from socio-economically better-off families.
The 4th point in your TL;DR seems wrong to me, though. What I understand from the text (in relation to socio-economic status of the family) is that daycare may even be good for babies of worse-off families even when the babies are really young, but that it is clearly negative for babies of better-off families until they are 3+.
You are correct. The relevant section is this (emphasis theirs):
All of that is for an average income family. Low-income children benefit from starting earlier, and high-income children from starting later. (It’s likely not just actual income that matters, but socioeconomic factors — but income is easy to measure objectively so researchers measure it.) The most deprived children can actually benefit from starting as 1-year-olds.
This is a pretty good summary of the research on daycare effectiveness. It is a Much More Than You Wanted To Know-style post from a science blogger criticalscience who has some interesting posts on Medium.
TL;DR:
weakerCORRECTION: worse for children from socio-economically better-off families.Childcare : what the science says