“…Approaches include: cost-benefit analysis (CBA); outcome rating scale (ORS); single outcome agreements (SOAs); social audit; social accounting and audit (SAA); and social return on investment (SROI) (Brooks Jr, 1980;Gao & Zhang, 2006;Gibbon & Dey, 2011;Gray et al, 1997;Medawar, 1976;Miller et al, 2003;Natale & Ford, 1994;NZIER, 2012;Owen et al, 2000;Zadek, 1993). In addition, single measure valuation techniques also include replacement cost, opportunity cost and numerous stated preference techniques (for example, contingent valuation, choice experiment, and revealed preference methods) (Cnaan and Kang, 2010). These techniques assume there is a market for a TSO's activities and that 'customers' are present to value these activities.…”