Editorial: Ingenious designs and causal inference in child psychology and psychiatry.

The embryology of behavior--This title of a book by the great developmental psychologist Arnold Gesell (Gesell, 1945) continues nicely to encapsulate for me a core endeavour in child psychology and psychiatry; in the use of scientific method to tease out causes and processes within developmental science and psychopathology. This edition of JCPP includes some tremendous examples of the increasing rigour and sophistication with which such questions are being addressed. Particularly encouraging for me, as primarily an interventionist, is the use of well-designed randomized controlled trials (RCTs) for that end.