Should the use of standardized baselines in the CDM be mandatory?

There has been considerable debate on the merits of standardized baselines (SBLs) in the clean development mechanism (CDM), and how such baselines could reduce transaction costs for CDM projects. It has not been considered whether the voluntary versus mandatory use of SBLs by CDM project developers can affect the environmental integrity of the CDM. An example is given in which SBLs are applied to a homogeneous output industry in order to illustrate how the voluntary use of SBLs could lead - even with relatively stringent benchmarks - to over-crediting of emission reduction credits.