A common practice among health-care professionals is to determine the severity of a patient’s pain by asking them to rate their pain from 0 (no pain) to 10 (worst pain). It’s a quick and easy way, but research indicates it may not be reliable.

Until now no one has bothered to evaluate the accuracy of the widely-used numeric rating scale (NRS) and with the Joint Commission of Accreditation of Healthcare Organization requiring accredited hospitals and clinics to routinely assess all patients for pain its effectiveness needs to be established.

Researchers at the Indiana University School of Medicine and the University of North Carolina found that although the NRS is easy to administer, it failed to identify approximately one-third of patients with long-term pain serious enough to impair day-to-day functioning. The patients in the study had long-standing pain and many had more than one pain issue.

Patients with short-term pain were not part of the evaluation for the accuracy of pain ratings.

The researchers noted that because the NRS focuses on current pain, a lot of patients with intermittent pain symptoms are overlooked. Another problem the researchers found was that a patient may refer to their pain as a discomfort and as such did not respond accurately when asked about pain.