Historical amnesia besets the consensus that Britain faces an unprecedented "crisis of childhood", and of child well-being. Drawing on evidence about changing uses of instruments and measures of well-being over time, this article explores and critiques claims about historical change and trends over time that are central to the imagined crisis of childhood in both diagnostic and therapeutic terms. It argues that diagnostic labels about the state of children's well-being arising from changing methodologies and measures, and the therapeutic and pedagogical models they create, cannot be isolated from social conditions. This means that claims about a crisis of childhood, and the kinds of interventions that follow, require critical debate and cautious application. In the current climate of crisis, however, such reflection and debate are notable only by their absence.