“…More recently, attention has focussed on the elaboration of definitions of response (Dougados et al, 2000;Ehrich et al, 2000;Pham et al, 2004;Bellamy et al, 2005a;Tubach et al, 2005a;Bellamy et al, 2005b;Bellamy et al, 2004a;Bellamy and Wilson, 2007a;Kvien et al, 2007) and state-attainment (Kvien et al 2007., Tubach et al, 2005bBellamy et al, 2004b; for hip and knee OA patients. The concepts of standardised measurement in OA using valid reliable and responsive instruments has been recognised in US Food and Drugs Administration (FDA) (US FDA,1999), European Agency for the Evaluation of Medicinal Products (EMEA, 1998), OARSI (OARSI Task Force, 1996;Maheu et al, 2006), IMMPACT (Turk et al, 2003;Dworkin et al, 2005) and OMERACT (Bellamy et al, 1997a) Guidelines. These guidelines principally concern research-based applications.…”