Indicadores: quanta complexidade é desejável ?
Philip Musgrove

Indicators: How Much Complexity is Desirable?
Philip Musgrove

A great many specific topics could be treated under the heading of “methodological aspects of indicators”—purposes, definitions, data needs, methods of calculation or estimation, accuracy, sensitivity, specificity, potential uses, and so on. This paper approaches the subject not through any of these topics, but by looking at several indicators and trying to draw some conclusions from them about how to make up good indicators for moderately complex situations. That is, all the indicators considered involve at least two measurable variables; and they are sometimes built up from other indicators which are already generally accepted as adequately representing simpler concepts.
All the examples chosen, except the first, are ones with which I have had some personal involvement, in making them up, criticizing them, or both. I think some useful lessons can be drawn from these cases—lessons about what to do, or in some cases, what not to do. The principal lessons concern the right degree of complexity of an indicator—how many variables to base it on, how to relate them to one another, and how to assure that the result is understood by whoever needs to understand it. This is particularly important when the indicator is to be used directly to determine the allocation of resources, or indirectly to influence such decisions.