“…The other equations of Approach 3, as well as Approaches 7 and 8, take merely the expenditure or payment, which makes the strong assumption of prices being at the equilibrium point of the perfectly competitive market model, requiring fulfilment of all conditions characterising such markets (Folland et al, 2010;Henry & Searles, 2012). This is unlikely given market imperfections in healthcare of, for example, quasi-monopolies and price controls, information asymmetries, patents and licencing requirements, and non-identical products (Arrow, 1963;Henry & Searles, 2012;Lave et al, 1994;Rattinger, Jain, Ju, & Mullins, 2008). Hence, spending £1 is unlikely to generate a benefit (revenue) equivalent to £1.…”