Several studies have established that there is considerable variance in semantic role assignment performance across different semantic roles within systems (Carreras and Màrquez, 2004;Carreras and Màrquez, 2005;Pado and Boleda Torrent, 2004).
these studies used either the PropBank semantic role paradigm (Carreras and Màrquez) or a limited of experimental conditions (Pado and Boleda).