Several factors need to be kept in mind when choosing indicators
(and, where appropriate, targets) for SEA: - should they be
input or outcome indicators/targets? - should social and
economic indicators/targets be included? State, pressure,
response; input, outcome Indicators and targets can be divided
into three types: - state indicators that describe the state of
the environment, for instance ambient NOx levels; - pressure
indicators that describe human pressures on the environment, for
instance emissions of NOx; and - response indicators that
describe responses to these pressures, for instance 'Percentage
of cars with catalytic converters' or 'bus frequency on route
X'. A range of organisations, notably the OECD, use these
distinctions when describing their indicators. The distinctions
between state, pressure and response indicators are not always
so clear in practice, particularly for social and economic
issues. However they illustrate an important concept in SEA: the
distinction between inputs and outcome