It is important to take stock of the extent to developments in environmental CBA have found their way into actual assessment. This chapter looks at this from the perspective of a number of OECD countries across policy sectors such as energy, transport and environmental policy, via questionnaire responses. What this finds is that there are large variations in the extent to which CBA is being carried out, and the extent to which various environmental impacts are being taken into account in these analyses, across economic sectors and across analytical contexts. For example, energy sector investments and policy proposals are relatively well covered in CBAs, but there is far narrower coverage of non-climate environmental impacts in those assessments. Cataloguing such use is important. Of course, it does not of itself provide answers to inevitable questions about why CBA is used in one context but not another. Nor did the responses provide a clear picture of the influence of CBAs on the final decisions. It must also be recognised that use and influence are moving targets in the sense that both are probably evolving reasonably rapidly given developments in environmental CBA.

Questions about why patterns of use and influence are how they are bound up with political economy, necessitating a richer understanding of the policy formulation process. If, in the extreme, all decisions were to be made on the basis of CBA, decision makers would have no flexibility to respond to the various influences that are at work demanding one form of policy rather than another. In short, CBA, or, for that matter, any prescriptive calculus, compromises the flexibility that decision makers need in order to “act politically” or meet other policy objectives. Unsurprisingly, this constrains use or shapes the nature of use in particular ways. Political economy then seeks to explain why the economics of the textbook is rarely embodied in actual decision-making and related to this, policy-formulation processes. But explaining the gap between actual and theoretical design is not to justify the gap. So while it is important to have a far better understanding of the pressures that affect actual decisions, the role of CBA remains one of explaining how a decision should look if the economic approach is adopted.

A significant array of decision-guiding procedures is available. This chapter shows that they vary in the degree of comprehensiveness where this is defined as the extent to which all costs and benefits are incorporated. In general, only multicriteria assessment (MCA) is as comprehensive as CBA and may be more comprehensive once goals beyond efficiency and distributional incidence are considered. All the remaining procedures either deliberately narrow the focus on benefits, e.g. to health or environment, or ignore cost. Procedures also vary in the way they treat time. Environmental impact assessment and life-cycle analysis are essential inputs into a CBA, although the way these impacts are dealt with in “physical terms” may not be the same in a CBA. Risk assessments, of which health-health analysis and risk-risk analysis are also variants, tend to be focused on human health only. The essential message is that the procedures are not substitutes for each other.