Most children will exhibit ODD type behaviours at some point in their childhood. In particular, during toddlerhood when many children experience the 'Terrible Two's' and during the teenage years when it is 'normal' for adolescents to exhibit a range of challenging and discordant behaviours similar to those of ODD children.
ODD is therefore diagnosed because of the frequency, perseverence and severity of these behaviours. Diagnosis requires at least four of the eight behaviours identified above to be present for at least six months. Some behaviours may wax and wane depending on other factors affecting the child and their family but will tend to be consistent over time.