# Sleep Training, Breastfeeding and Daycare: What the Research Says

> What the research says about sleep training, breastfeeding, daycare and more, from Emily Oster's Cribsheet.

Stage: baby - Topic: Approaches - Page: https://www.askcladle.com/guides/baby/oster-cribsheet

Grounded in: Emily Oster's *Cribsheet: A Data-Driven Guide to Better, More Relaxed Parenting, from Birth to Preschool*, and her ParentData newsletter., not quoted.

## TLDR

- Many early-parenting debates rest on weak studies; for many choices the honest answer is that differences are small.
- Breastfeeding has real short-term benefits, and fed is what matters most. Sleep training studies show no lasting harm; not doing it is fine too.
- Back-sleeping is strongly supported. Use her evidence to ease guilt, not to override your pediatrician.

## The approach

Many heated early-parenting debates rest on studies that cannot separate cause from correlation
(families who make one choice differ in many other ways). Oster separates the better studies
(randomized trials, careful comparisons) from the weaker ones, and argues that for many choices the
honest answer is "the differences are small - choose what works for your family".

## Examples she discusses (her reading of the evidence)

- **Breastfeeding:** real short-term benefits are well supported (for example fewer
  gastrointestinal infections, and some evidence for fewer ear infections and less eczema in
  infancy), while many long-term claims (IQ, obesity) look weaker once family differences are
  accounted for. Fed is what matters most; feeding decisions should not be driven by guilt.
- **Sleep training:** the studies she reviews do not find lasting harm to attachment or behavior
  and generally find it improves sleep; not sleep training is also a fine choice.
- **Safe sleep:** back-sleeping is strongly supported. On bed-sharing she discusses how risk
  concentrates in particular circumstances (sofas, smoking, alcohol, very young babies); the AAP
  still recommends room-sharing without bed-sharing, and Cradle follows the AAP on safe sleep.
- **Daycare vs. home, screen time, potty training, early learning:** effects in good studies are
  generally small; quality of care and family fit matter more than the category.
- **Vaccines:** she is clear the evidence supports vaccinating on the recommended schedule.

## Her framework for decisions (from The Family Firm)

In *The Family Firm* she suggests running family decisions like a thoughtful organization:
**frame the question, fact-find, make a final decision, and follow up** - and to agree on the
family's "big picture" priorities first, so individual decisions have something to be judged against.

## How to use this well

Useful for relieving guilt and making informed trade-offs. It is population-level evidence, not a
statement about one child, and it does not override the pediatrician on medical questions.