Tillett W, Shaddick G, Jadon D, Robinson G, Korendowych E, McHugh N. Novel composite radiographic score for longitudinal observational studies of psoriatic arthritis: a proof-of-concept study. J Rheumatol 2016; doi:10.3899/jrheum.150114. In the print version of the article, and the PDF version (available online), the total possible number of points for the Reductive X-ray Score for Psoriatic Arthritis is incorrect. It should be 234. The change applies to the Abstract (under Results), in the first paragraph under Results in the text, and to the last row of Table 2.
These corrections have been made to the online version of the article.