SEW created the Star diagram to facilitate a graphic and visual recognition of progress toward or regress from a more sustainable energy system. It is an eight-pointed orientor star modified with the use of a "unit" circle that typically identifies the 1990 level of the measured indicator and with a center-the sustainability target-with a value of "zero¹⁸." While each indicator can be charted individually-growth of CO₂ emissions per capita, for example or access to electricity in rural households-either within each nation or collectively for a region or the world, an integrated Star diagram brings all of the indicators together in one stimulating and memorable form. Observers can compare progress over time by the dynamic changes in the diagram, or even compare progress in different countries. The indicators measure differing system conditions, and while the scales are integrated to values between zero and one, the scales are not identical; some indicators have vector values great-er than one, others do not. Some can have values less than zero (if the sustainability target is exceeded). Since the scales of measurement differ between each indicator, however, the area of the Star from year to year is not a measure of overall sustainable energy development. Each indicator tends towards the center of the Star if genuine progress is being measured. Regress away from sustainable development-in other words, worsening conditions are being measured-will appear as values greater than "one;" in some instances values as high as "five."

A sample Star appears below to illustrate the diagram (not based on real data).

The center of the circle is a value of "zero," indicating the country has achieved the objective defined as sustainable for that particular indicator. For example, using Indicator #1, this would mean that the country reduced its emissions of carbon dioxide per capita to a fraction of the 1990 global average. Clearly, some sustainability objectives are extremely difficult to accomplish, and will take decades to reach in many countries, whereas other indicators may already be largely fulfilled in some countries. An example of the latter is Social Indicator #3-percent of households having access to electric power. This remains a valid indicator for most of the world's population, however, as access to electricity is considered a social good yet lacking for more than 1.5 billion people worldwide.

Indicators number 1, 7, and 8 measure each country's progress relative to 1990 global averages, whereas the other indicators are relative that country's performance in 1990.

Note: Discuss the position of each indicator on the Star. I think we suggested that each binary (e.g., social, economic) indicator is placed on opposite sides of the Star.

Note2: We must produce a scaled and labeled Star with indicators properly positioned.