Functionalities of indicators and role of context

1. Functionalities of indicators and role of context Robert Joumard & Henrik Gudmundsson 1. Definition of an ‘indicator’ 2. Characteristics of indicators as measurement tool 3. Characteristics of indicators from the use point of view

2. Objectives • Synthesis of the 2nd and 3rd WG 1 presentations • J. Borken and H. Gudmundsson: The context always matters • R. Joumard, G. Arapis and T. Goger: Environmental indicators: The context is not an important parameter, but environmental aspects (chain of causalities) • H. Gudmundsson: Indicators as tools for measurement and decision making • R. Joumard: Definitions of physical and policy contexts of EST indicators • How to define the concept of indicator? • How contextual factors should be taken into account? RJ07-148

3. Indicator definitions (1/3) • 3 types of definitions • a sentry, sentinel, revelation, indicating the presence or absence of something • a measurement tool • a definition by its using • The key notion is representation: An indicator has to represent something in an adequate way • At the same time it has to allow simplification compared to a full representation • Representation necessarily involves 3 elements • the thing being represented • the thing representing it (the indicator) • the usage domain (the entity for whom the representation has to be valid; acceptable) RJ07-149

4. Indicator definitions (2/3) • Distinguish clearly the two fields of thought • the characteristics of the measurement tools: The measurement aspect is fundamental to any indicator, and can be one starting point • the characteristics of the uses: The decision context and use is essential for indicators to be used for achieving sustainability and sustainable transport: it is a ‘filter’ for purely measurement based indicators. • Both have to be present however, in order the indicators of EST can be fully accepted RJ07-150

5. Proposed definition of an ‘indicator’ (3/3) An indicator is a variable, based on measurements, representing as accurately as possible and necessary a phenomenon of interest to human beings. An environmental impact indicator is a variable based on measurements, representing an impact of human activity on the environment, as accurately as possible and necessary. An indicator of environmentally sustainable transport is a variable, based on measurements, representing potential or actual impacts on the environment, or factors that may cause such impacts, due to transport systems, flows or policies, as accurately as possible and necessary. RJ07-151

6. 2 meanings of ‘context’ • The context of use and decision making: the purpose and aim of using certain indicators • e.g for planning, verification, control, information etc • The physical context in which the particular impact is measured: the specific physical characteristics of the surroundings • 2 questions essential to define the indicators as measurement tool • What to measure? • How to measure? RJ07-152

7. What to measure? (1/3) • An environmental indicator is a tool to measure the impacts (or a given impact) upon the environment of an activity • The impacts considered have to be defined • greenhouse effect ≠ global warming ≠ average temperature increase • the average concentration of a gas in the atmosphere • number of species lost ≠ biodiversity • noise level ≠ number of people exposed at more than 65 dBA ≠ impact of noise on humans • or the impacts on the environment considered as a whole... • Describing the chain of causalities from initial cause to final impact is essential to clarify what, precisely, the indicator is measuring RJ07-153

8. What to measure? (2/3) • Describing the chain of causalities from initial cause to final impact is essential to clarify what, precisely, the indicator is measuring • Chain of causalities of greenhouse effect may include • transport demand - traffic - emissions - dispersion + chemical transformation of pollutants - equilibrium with sinks - greenhouse effect - climate change - local temperature and humidity, sea level changes - disappearance or modification of ecosystems (incl. humans) - effects on the ecosystems and humans (health, economy, international tensions…) • For each step may be a unique indicator that best represents this step • In some cases measures of one step could serve as indicator for the previous or following steps • especially when an indicator is used for evaluation (and not to measure something existing, as the noise level in a given location) RJ07-154

9. What to measure? (3/3) • The activity has to be defined • A particular measurement tool may be designed for some activities but not necessarily all • For instance, the noise equivalent level Day-Evening-Night LDEN = indicator of annoyance, based on weighted acoustic energy level Leq for the 3 periods • But Leq (and then LDEN) not adapted to short and high noise level as TGV or aircraft noise • Leq and LDEN not (universal) noise indicators, but road traffic noise indicators RJ07-155

10. How to measure? (1/3) • An indicator should answer firstly the requirements of any measurement tool: representativity of what it measures (at the best, proportionality), accuracy • the best indicator would give the exact and precise level of the impact of the studied activity on the environment • Context (local physical characteristics) can play an important role in the impact on the environment: • period of the source, position of the source (altitude, urban/rural), initial state of the environment, number and types of targets… RJ07-156

11. How to measure? (2/3) • To measure precisely such impacts, several possibilities: (A)the full modelling of the chain of causalities is the most accurate way, but it is complex and expensive, far from the simplicity of the indicator approach (B) The impact does not depend on the geographical or temporal source characteristics, neither the stake holders • as the global impacts: greenhouse, ozone depletion, non renewable energy… (C) To build a simple function taking into account the local characteristics through simple parameters (as density of population, height of the quarters…) (D) To build a function taking into account average unit impacts, as number of annoyed people per veh.km for a type of urbanisation (town center/suburbs/rural) RJ07-157

12. How to measure? (3/3) B impact not depending on geographical / temporal source characteristics D unit impact per veh.km accuracy Environmental indicators Simplicity of the indicator C unit impact per veh.km, depending on type of context A Full modelling of chain of causalities Full models, Not indicators Weight of the local characteristics in the chain of causalities RJ07-158

13. Indicator characteristics from the user point of view (1/2) • Why to measure? • measure the impact • understand a situation • decide the "best" project, plan, policy, product • raise awareness of problems • characteristics of indicators relating to social & perceptual context: • transparency of measurement and design methods • acceptance by the users • understandability • interpretability (positive function of the impact, additivity, meaningfulness) • availability of trusted input data RJ07-159

14. Indicator characteristics from the user point of view (2/2) • A tool, as a step of a reasoning • a tool cannot replace the reasoning • the perception of problem, the question, or the solution, therefore the reasoning, are context dependent. • does not mean that the indicators used to measure has to depend on the context • means that the measurement function is only one necessary but not sufficient step in choosing the proper indicators • Requirements / reasoning • Are there potential bias in the data or are they objective? • What are the main explaining parameters of the situation? • Is-it possible to transform a correspondence into a causality? • Does the indicator measure really what I would like? • Is the indicator applicable to the conditions studied? RJ07-160

15. Functionalities of indicators and role of contextconclusion • An indicator is a variable, based on measurements, representing as accurately as possible and necessary a phenomenon • What to measure? • How to measure? • Why to measure? • The measurement does not replace the reasoning RJ07-161