In resource economics, Hartwick's rule defines the amount of investment in produced capital (buildings, roads, knowledge stocks, etc.)
This investment is undertaken so that the standard of living does not fall as society moves into the indefinite future.
Genuine savings has been estimated for many countries by the World Bank and other authors (Hamilton and Atkinson, 2006, chapter 6).
A positive value for a nation's genuine savings has been linked to the possibility of long-run economic sustainability.
Ecological economist Clive Spash criticized Hartwick's Rule for its "self-evident lack of realism".