Characteristics of effective indicators
- Effective indicators are relevant; they show you something about the system that you need to know.
- Effective indicators are easy to understand, even by people who are not experts.
- Effective indicators are reliable; you can trust the information that the indicator is providing.
- Lastly, effective indicators are based on accessible data; the information is available or can be gathered while there is still time to act.
An example of an indicator is the gas gauge in your car. The gas gauge shows you how much gasoline is left in your car. If the gauge shows the tank is almost empty, you know it's time to fill up. Another example of an indicator is a midterm report card. It shows you whether a student is doing well enough to go to the next grade or if extra help is needed. Both of these indicators provide information to help prevent or solve problems, hopefully before they become too severe.
Indicators can be useful as proxies or substitutes for measuring conditions that are so complex that there is no direct measurement. For instance, it is hard to measure the 'quality of life in my town' because there are many different things that make up quality of life and people may have different opinions on which conditions count most. A very simple substitute indicator is 'Number of people moving into the town compared to the number moving out.'
Examples of familiar measurements used as indicators in everyday life include:
- Wave height and wind speed are indicators of storm severity
- Barometric pressure and wind direction are indicators of upcoming weather changes
- Won-lost record is an indicator of player skills
- Credit-card debt is an indicator of money-management skills
- Pulse and blood pressure are indicators of fitness
Note that these are all numeric measurements. Indicators are quantifiable. An indicator is not the same thing as an indication, which is generally not quantifiable, but just a vague clue. In addition to being quantifiable, effective indicators have the four basic characteristics noted above. These characteristics are:
An indicator must be relevant, that is, it must fit the purpose for measuring. As indicators, the gas gauge and the report card both measure facts that are relevant. If, instead of measuring the amount of gas in the tank, the gas gauge showed the octane rating of the gasoline, it would not help you decide when to refill the tank. Likewise, a report card that measured the number of pencils used by the student would be a poor indicator of academic performance.
An indicator must be understandable. You need to know what it is telling you. There are many different types of gas gauges. Some gauges have a lever that moves between 'full' and 'empty' marks. Other gauges use lights to achieve the same effect. Some gauges show the number of gallons of gasoline left in the tank. Although different, each gauge is understandable to the driver. Similarly, with the report card, different schools have different ways of reporting academic progress. Some schools have letter grades A through F. Other schools use numbers from 100 to 0. Still other schools use written comments. Like the gas gauge, these different measures all express the student's progress or lack of progress in a way that is understandable to the person reading the report card.
On the other hand, a gas gauge that showed the number of BTU's left in the tank would probably not be very useful to you in deciding when to fill up the tank. Likewise, a report card that gave grades in ancient Greek script would be a mystery to most people. In order for you to know when action is needed, you must be able to understand what an indicator is telling you.
An indicator must be reliable. You must trust what the indicator shows. A good gas gauge and an accurate report card give information that can be relied on. A gas gauge that shows the tank is empty when in fact it is half full would make you stop for gasoline before it is needed. A gas gauge that shows the tank is half full when in fact it is empty would cause you to run out of gas in an inconvenient place. Similarly, if a student's grade were reported wrong, an honors student could be sent for remedial work and a student who needs help would not get it. An indicator is only useful if you know you can believe what it is showing you.
Reliability is not the same as precision. When your gas gauge registers empty, you know there is still a gallon or so of gasoline left as a reserve. The gas gauge reliably under-reports the amount of gasoline. An indicator does not necessarily need to be precise; it just needs to give a reliable picture of the system it is measuring.
Indicators must provide timely information. They must give you information while there is time to act. For example, imagine a gas gauge that only gave you the amount of gasoline in the tank when the engine was started. After you have been driving for several hours, that reading is no longer useful. You need to know how much gasoline is in the tank at each moment. Similarly, a report card distributed a week before graduation arrives too late to give a student remedial help. In order for an indicator to be useful in preventing or solving a problem, it must give you the information while there is still time to correct the problem.
One of the biggest problems with developing indicators of sustainability is that frequently the best indicators are those for which there is no data, while the indicators for which there is data are the least able to measure sustainability. This has led many communities to choose traditional data sources and measures for indicators. There are several advantages to traditional indicators. First, the data is readily available and can be used to compare communities. Second, traditional indicators can help to define problem areas. Third, traditional indicators can be combined to create sustainability indicators.
However, there is a real danger that traditional data sources and traditional indicators will focus attention on the traditional solutions that created an unsustainable community in the first place. It may be tempting to keep measuring 'number of jobs,' but measuring 'number of jobs that pay a livable wage and include benefits' will lead to better solutions. Discussions that include the phrase 'but you can't get that data' are not going to lead to indicators of sustainability. In fact, if you define a list of indicators and find that the data is readily available for every one of them, you probably have not thought hard enough about sustainability. Try to define the best indicators and only settle for less as an interim step while developing data sources for better indicators.