So, if adolescents in New York City, across the state and nationally are dutifully checking into emergency rooms when they suffer a traumatic brain injury (a concussion or other head trauma), and ER doctors are duly reporting such incidents, things are being tracked reasonably well, right?

According to a new study co-authored by a major children’s hospital and the national Centers for Disease Control and Prevention, such a conclusion could hardly be more misplaced.

In fact, it is that very reliance on emergency room-derived data relating to children’s head injuries that is the central culprit contributing to an erroneous understanding of the topic nationally.

And here’s why, say the researchers: Although widely accepted data centering on adolescent head trauma is often based solely on information forthcoming from emergency rooms, those venues are in fact visited comparatively infrequently by children with brain injuries.

In fact, say the joint study authors from the CDC and The Children’s Hospital of Philadelphia, only about 12 percent of the children in their survey received a concussion diagnosis in the first instance from an emergency room.

The valid conclusion to be derived from close study of pediatric concussion data is actually this, say researchers: Such injuries are being materially underreported across the country.

It is really a primary care doctor who makes the concussion call most of the time. One of the study co-authors says the fact that 80 percent of kids with concussions initially receive that diagnosis from a family or primary care physician underscores “the critical importance of providing targeting training and resources in primary care settings.”

And the reason for that is obvious: If it’s docs on the front line who are most often identifying adolescent concussions and other types of head injuries, they’d better be getting the diagnosis right.