The underlying objective of these responses is that these actions lead to measurable progress in terms of impacts (i.e. reduced pressures, and thus improvement in the state of the environment). Responses refer to environmental, general economic and sectoral policies and changes in awareness and behaviour - via government, households and firms, with examples of indicators including environmental expenditures, environmentally related taxes and subsidies, and enforcement and compliance activities (OECD, 2006). The conceptual framework used here to monitor and evaluate mainstreaming responses can be further elaborated by a conceptual framework that depicts the mainstreaming responses as a system whose key components include inputs, processes (or activities), outputs, outcomes and impacts.