The Numerical Rating Scale (NRS) is a common measure used for subjective pain assessment. It typically involves asking a patient to rate the intensity of their pain on an ascending scale ranging from 0 or 1 up to 5 or 10. To address disagreement about the most valid and reliable format of the NRS to use in clinical practice, the source article evaluated the use of NRS versions of various increments with patients experiencing chronic pain. The researchers concluded that NRS versions with 11-point and 21-point scales are comparable psychometrically to the original 101-point version and should be used preferentially because they are presumably easier for patients to understand.
Measures Registry
Numerical Rating Scale (NRS)
Description
Purpose
The NRS provides a method for patients to self-report their pain intensity. The source article demonstrated that the NRS does not need to be administered on the 101-point scale, and that the 11-point and 21-point scale versions offer sufficient levels for patients to use to describe their pain intensity.
Population
Patients experiencing chronic pain
Year of Publication
1994
Reference
Jensen, M. P., Turner, J. A., & Romano, J. M. (1994). What is the maximum number of levels needed in pain intensity measurement? Pain, 58, 387-392. https://doi.org/10.1016/0304-3959(94)90133-3
Number of Items
4
Scale Types (Likert=Likert Type; MC=Multiple Choice; T/F=True/False; OR=Open Response)
Likert Type
Likert: The range of points on the Likert scale depends on the version of the NRS being used (e.g., 11-point, 21-point, etc.)
Subscales
Current Pain
Worst Pain
Least Pain
Average Pain
Scoring
The scores are determined by how the patient rates their pain using the visual scale in response to the four items. Given the range of response options, patient scores on the original 101-point NRS scale were often rounded by the researchers to fit into the lower point level of the NRS scale being tested (e.g., 11-point scale). Additional information can be found within the ""Pain Intensity Measures"" heading of the Method section.
Administration
Self-Administered
Readability/ Literacy Level
N/A
Reliability
N/A
Validity
To assess the validity of the 11-point and 21-point scale versions of the NRS, patient scores on these versions were compared to patient scores on the full 101-point scale. Table 1 in the source article displays the correlation coefficients between the full 101-point scale of the NRS and the two shorter versions of the scale. For both the 11-point and the 21-point scale, the correlation coefficients were 0.99 or higher, demonstrating high validity of the shorter versions of the scale with the full 101-point scale. Of note, the researchers also tested shorter versions of the scale (i.e., 6-point, 4-point, 3-point, and 2-point). The correlation coefficients were lower than 0.98 for these versions of the full 101-point scale, with the lowest found for the 2-point scale (range of 0.43 to 0.84).
Limitations
The source article used pain intensity scores reported by patients on the original 101-point version of the NRS to recode scores for the shorter versions of the measure (e.g., 21-point, 11-point, etc.). For this reason, the results may have been different had the patients actually rated their pain using the different versions of the NRS. However, the researchers intentionally chose to recode patient scores on the original 101-point version of the NRS rather than re-administer various versions of the NRS to the patients to avoid biased responses to future versions of the measure based on the previous ones already completed.
Availability
Publicly Available
Cost
Free
Other Considerations
N/A