**3.5 Proximity-to-target performance indicator**

To measure ecological and management oriented policy categories, such as for example the wise and sustainable use of forest resources, requires a set of different measurable indicators and data. Some are easily measurable with instruments and metrics, and others by judgement, often value laden along a scale. Performance indicators on social level usually refer to different kinds of reference conditions and values, such as national or international policy targets. Especially demanding, both technically and politically, is the implementation of sustainability performance indicators. Often they are very vague and difficult to follow up and address with responsible authorities or actors. European Environmental Agency (EEA, 2007) has defined the usefulness of a proximity-to-target approach:

*"… concept of environmental performance evaluation is being developed for use in an environmental management system to quantify, understand and track the relevant environmental aspects of a system. The basic idea is to identify indicators (environmental, operational and management) which can be measured and tracked to facilitate continuous improvements. Performance indicators compare actual conditions with a specific set of reference conditions. They measure the 'distance(s)' between the current environmental situation and the desired situation (target): 'distance to target' assessment."* 

Proximity-to-target indicators are a type of environmental performance indicator designed for ranking, benchmarking and monitoring action towards well defined and measurable objectives. The proposed CFEMI is an extension of the concepts and principles from both the macro (societal) and micro (corporate) levels including mimicry of the proximate-to-target indicator from '*Pilot 2006 EPI Environmental Performance Index*' launched by Esty et al. (2006).

### **3.6 Reliability of measurements**

To make high quality, representative measurements of forest variables, is a challenge. West (2004) gives an account of *accuracy* as the difference between a measurement or estimate of something and its true values, *bias* as the difference between the average of a set of repeated measurements or estimates of something and its true value, and *precision* as the variation in a set of repeated measurements or estimates of something.

Because much of the measurement phase of the field work is dependent on assessment of the values for the different variables, the indicator is vulnerable to the skills and experience of the observers. Within a close collaborating group of local foresters the observations can be sufficiently accurate, but comparing the results between different forests and assessment teams, the assessment could vary significantly.
