When estimating the age of an infant or child, which of the following is not a useful indicator?

Estimating the age of an infant or child can involve a range of indicators; however, the level of consciousness is not particularly reliable in determining age. While the level of consciousness can give insight into a child's immediate health status and potential neurological functioning, it is more a reflection of their current state than an objective measure of developmental milestones or age.

In contrast, physical size is a more direct indicator since growth patterns correlate with age in children. Emotional responses can also provide insight, as certain emotional and social behaviors develop with age. Interaction with the first responder can reveal how a child communicates and responds to social cues, which typically improve as the child gets older.

Given these points, while the level of consciousness is important for assessing a child's condition, it does not serve as a useful indicator for estimating their age accurately.