Understanding childhood, including the one you accompany

Responsible eldest, rebellious youngest: the typology is old and popular. Large analyses published since 2015 recover almost nothing of it.

Testing an experiment again is difficult everywhere. When the participants are twelve months old, it becomes a problem of organisation as much as of method.

International child well-being league tables circulate widely. Their result depends at least as much on the chosen weightings as on the situations described.

An association between a parenting practice and a child outcome may be produced by neither of them. Recent designs make it possible to test that.

A 2010 article showed that nearly all published work concerned a tiny fraction of humanity. The correction is under way, slowly.

One hundred and twenty-three children, followed for forty years, supplied the central argument for investing in early childhood. The sample size is also the main objection.

A figure like zero point four circulates widely in educational syntheses. Knowing what it measures prevents comparing it to what it does not.

Heritability is one of the most misunderstood words in statistics. It does not describe an individual, and its value changes with the population in which it is computed.

Most data on young children come from questionnaires completed by an adult. That source has well identified properties, rarely recalled when the results circulate.

Following the same thousands of children for twenty years is expensive and takes twenty years. It is nonetheless the only design that separates what comes before from what comes after.