BOX 2J
BAROMETER OF STABILITY

Robert Prescott-Allen

The Barometer of Sustainability is a tool for measuring and communicating a society's well-being and progress toward sustainability. It provides a systematic way of organizing and combining indicators so that users can draw conclusions about the conditions of people and the ecosystem and the effects of people-ecosystem interactions. It presents those conclusions visually, providing anyone, from villager to head of state, with an immediate picture of human and ecosystem well-being.

Six key features of the Barometer are:

• It is a performance scale. As such it combines indicators to which the user can attach a performance value. Indicators are chosen by defining values for them that would be desirable, acceptable or unacceptable with respect to human or ecosystem well-being. Indicators that are neutral or of unknown significance are excluded. 
• The scale has two axes, one for human well-being, the other for ecosystem well- being. Conclusions about the conditions of people and the ecosystem, an index of human well-being and an index of ecosystem well-being, are expressed as points on their respective axes. The intersection of these points provides a reading of overall well-being and progress toward sustainability, The separation of human and ecosystem well-being ensures that an improvement in human well-being does not mask a decline in ecosystem well-being, or vice versa. 
• A lower score on one axis overrides a higher score on the other: the reading of overall well-being and sustainability is based on whichever subsystem (the society or the ecosystem) is in worse condition. This is to prevent an improvement in ecosystem well-being being from being understood as compensating for a drop in human well-being, or vice versa. Thus the Barometer does not allow a trade-off between human well-being and ecosystem well-being, reflecting a view that people and the ecosystem are equally important and that sustainability is a combination of human well-being and ecosystem well-being. 
• The Barometer's 100-0 scale is divided into five sectors of 20 points each, plus a base of zero. The division into five sectors allows the user to control the scale by defining one or more of the sectors. This feature makes the Barometer a more powerful performance scale than if only the end points were defined. When only the end points are defined, results can appear odd or even absurd. For example, child mortality rates range from 5 deaths per 1,000 live births (Finland today) to 400 deaths per 1,000 (Mali in 1960). If best is defined as 0 deaths and worst as 400 deaths, then a country with 75 deaths per 1,000 would still fall in the top fifth of the scale (the good sector); and only a country with 320 or more deaths per 1,000 would fall in the bottom fifth (the bad sector). This would not matter if the only purpose of the scale was to rank societies to see which ones perform best. The main purpose is not to see if a society is doing better than others, but if it is doing well. 
• Defining the sectors of the scale extends a series of judgements that starts with definitions of sustainable development, ecosystem well-being and human well- being, and continues through the choice of issues to be assessed and the selection and interpretation of indicators. It obliges users to state explicitly their assumptions about the significance of each indicator for human or ecosystem well-being, and the levels of achievement that would be ideal, desirable, acceptable, unacceptable, or disastrous. This process of value-based judgements is common to all assessment and decision making. But with the Barometer scale, it is acknowledged up front and made explicit throughout. 
• Converting indicator results to the Barometer scale involves a simple calculation. Formulae, accessible only to people trained in statistics or indices, have been deliberately avoided. Ease of use by a wide range of users is preferred to mathematical elegance or sophistication.

The main use of the Barometer is to combine indicators, enabling users to draw broad conclusions from an array of often confusing and contradictory signals. As such it can be employed in a wide variety of assessment methods. Environmental or ecosystem indicators are combined on the ecosystem well-being axis. All other indicators are combined on the human well-being axis. All that is required is to arrange indicators hierarchically, so that they can be combined into progressively more aggregated indicators, culminating in the highly aggregated indices of ecosystem well-being and human well-being. By making the aggregation steps clear, the big picture is gained without losing the information in the constituent indicators.

How different indicator sets would be arranged is shown in the table below, with examples from the Commission on Sustainable Development's framework for reporting on Agenda 21 (UN Commission on Sustainable Development 1996), the World Bank's four-capital framework (Serageldin 1995), The Well-being of Nations (Prescott-Allen in press), and the Human Development Index (e.g. UNDP 1996).

The Barometer can be used at any level, from local to international. It has been used in villages in India and Nicaragua, at the provincial level in British Columbia (Canada), and in The Well-being of Nations, an assessment of the sustainability of 180 countries (Prescott-Allen in press). The only differences of method between one level and another are in who chooses and interprets the indicators and how data are collected.

An additional function of the Barometer is as a communication tool. In Zimbabwe, for example, villagers preparing their own sustainable development action plans defined their own categories and labels for the sectors of the human and ecosystem axes. Then they discussed where they were on each axis. They went on to assess their condition and the state of their ecosystem in more detail. At the end of the assessment they reviewed their position on the Barometer. Positions on the axes of the scale were not calculated but were estimated qualitatively. The value of the Barometer was that it helped the villagers to consider people and the ecosystem together. and to see progress as improving the condition of both.

Converting indicator measurements so that they can be combined on the Barometer scale requires setting the end points and controlling the scale for each indicator. Setting the end points of the scale involves defining the best and worst measurement (100 and 0 points respectively).

Controlling the scale involves defining the sectors. An uncontrolled scale is the regular Barometer scale, with equal intervals from 1 to 100. Whether an indicator reading falls in the good, OK, medium. poor or bad sector is determined by the end points of the scale. For example, an unemployment rate scale set so that 0% is best ( l00) and 100% is worst (0) would result in an unemployment rate as high as 19% being classified as good; and an unemployment rate of 80% or above would be considered bad.

If the level of performance that would fall into the good, OK, medium, poor or bad sectors is appropriate for those sectors, then the scale does not need to be controlled. If it is not appropriate, then the scale must be controlled by defining one or more of the sectors.

The most important sectors are good and OK (particularly good), since they define human well-being and ecosystem well-being, the conditions of the good and sustainable life. Good performance means ideal or desirable performance. The good sector therefore needs to be defined exactly and will often include a narrower range of performance than the other sectors. For example, an unemployment rate of 0-4% may be considered good (a range of five percentage points), 5-9% OK (a range of five percentage points), 10-19% medium (a range of 10 percentage points), 20-49% poor (a range of 30 percentage points), and 50-100% bad (a range of 50 percentage points). Because the total range of performance is often wide and the window of good performance is often small, the scale is more likely to be controlled than uncontrolled.

A full account of how to use the Barometer, including the calculation method, is given in Prescott-Allen, The Well-being of Nations (in press).

REFERENCES

Prescott-Allen, Robert. The Well-being of Nations. In press.

Serageldin, Ismail (1995) Sustainability and the Wealth of Nations: First Steps in an Ongoing Journey. Third Annual World Bank Conference on Environmentally Sustainable Development. World Bank, Washington, DC.

UN Commission on Sustainable Development (1996) Indicators of Sustainable Development: Framework and Methodologies. United Nations, New York.

UNDP (1996) Human Development Report 1996. Oxford University Press, New York & Oxford.