Radiographs are important for assessing structural damage in patients with ankylosing spondylitis (AS); this technology was selected by the international ASsessment in Ankylosing Spondylitis (ASAS) Working Group as an important domain for assessing outcome in clinical trials. The selection of a preferred scoring method based on the OMERACT filter still needs to be undertaken. This article describes the scientific basis for and process of making the selection. Finally, both the ASAS Working Group and OMERACT participants voted for the modified Stoke AS Spinal Score (mSASSS) as the preferred scoring method for use in clinical trials in AS.