Error of pain measurement Iben Axén, Karolinska Institutet 6 July 2011 In the methods section, the pain measurement is described as a Numeric Rating Scale, which is correct. However, in the result section as well as in Table 1, pain is described as a measurement with the Visual Analogue Scale, which is incorrect. This fact has no bearing on the figures (means and SD) presented, but they should, of course, read "NRS" even in the result and in the Table. We apologize for this error. Competing interests I declare that I have no competing interests.