“…Evidence from research into the consistency of school effects between subjects (Luyten, 1998;Ma, 2001;Thomas, Sammons Mortimore, & Smees, 1997b) and differential school effects (Gray, Peng, Steward, & Thomas, 2004;Sammons, Nuttall, & Cuttance, 1993;Thomas, Sammons, Mortimore, & Smees, 1997a;Veenstra, 1999) shows that a general value-added indicator of school effectiveness masks all kinds of processes within the school that affect the progress of students. In an accountability system as in The Netherlands, which is based on identifying insufficient practices and schools as quickly as possible, a more sensitive system would be required in which multiple indicators of school effectiveness are simultaneously assessed, some of which are value added.…”