Learning to love the null

Children’s behaviour and mental health has the power to surprise us, readers and authors of the Journal of Child Psychology and Psychiatry and laymen alike, if not for the endless variation among people, then for the ever-changing context in which they develop. The hypothetico-deductive method in combination with null-hypothesis significance testing has turned surprise into scientific knowledge. Null effects may in themselves also be surprising and informative, but appear less well represented in the literature. This editorial highlights emerging methodological practices for studying null effects in the most informative way.