Capital theory and the measurement of sustainable development: an indicator of “weak” sustainability

"The measurement of sustainable development is not without considerable difficulties, yet this should not detract from the positive advances that can be made in this direction. In this paper we present one form that a “weak” sustainability indicator can take. Derived from a simple but intuitive savings rule, it incorporates the idea that the level of overall capital stock should be non-decreasing. Although subject to qualification at this stage, some interesting results emerge from the application of the rule to 18 countries."