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

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?

Objectives

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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)

Indicator definitions (1/3)

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Distinguish clearly the two fields of thoughtthe 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

Indicator definitions (2/3)

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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.

Proposed definition of an ‘indicator’ (3/3)

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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?

2 meanings of ‘context’

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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

What to measure? (1/3)

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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)

What to measure? (2/3)

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The activity has to be definedA particular measurement tool may be designed for

some activities but not necessarily allFor 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

What to measure? (3/3)

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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 environmentContext (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…

How to measure? (1/3)

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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)

How to measure? (2/3)

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How to measure? (3/3)

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Sim

p lic

ity

of t h

e i n

d ica

tor

Weight of the local characteristics in the chain of causalities

AFull modelling of chain of causalities

Cunit impact per

veh.km, depending on

type of context

Environmental indicators

Full models,Not indicators

accuracy

Dunit impact per veh.km

Bimpact not depending on geographical / temporal source characteristics

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

Indicator characteristics from the user point of view (1/2)

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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?

Indicator characteristics from the user point of view (2/2)

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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

Functionalities of indicators and role of context

conclusion

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