Longitudinal cohort study: what this kind of study can — and can't — tell parents

A large group of children is followed over years, with measures taken at several ages, so researchers can see what predicts what later on.

What it can show

It can show that an early experience does — or doesn't — predict later outcomes, across real childhood timescales.

What it can't

Families aren't randomly assigned, so findings remain associations; and a study only speaks to the outcomes it measured.

1 episode in the launch series uses this design:

Episode 9⏱ 3:11 video · 📖 1 min read

Longitudinal cohort study Video coming soon

Bed-Sharing With Your Baby Left No Mark by Age 11

Bilgin et al., Attachment & Human Development, 2024

Try tonight: Make your sleep-arrangement decision on current safe-sleep guidance and your family's real life — and let go of the fear that bed-sharing at 9 months, by itself, sets your child's behaviour path.

Questions about this design

What is a longitudinal cohort study?

A large group of children is followed over years, with measures taken at several ages, so researchers can see what predicts what later on.

Can a longitudinal cohort study prove cause and effect?

It can show that an early experience does — or doesn't — predict later outcomes, across real childhood timescales. Families aren't randomly assigned, so findings remain associations; and a study only speaks to the outcomes it measured.

Which Parenting by Science episodes use this design?

Episode 9 — “Bed-Sharing With Your Baby Left No Mark by Age 11” (Bilgin et al., Attachment & Human Development, 2024).

Meta-analysis (2)Systematic review & meta-analysis (2)Observational survey (1)Survey + classic experiments (1)Cross-sectional survey (1)Observational cohort study (1)Cross-sectional study (1)Within-person observational study (1)Randomized clinical trial (1)