Genuine progress indicator
Most economists assess progress in people's welfare by comparing the gross domestic product over time—that is, by adding up the annual dollar value of all goods and services produced within a country over successive years. However, GDP was not intended to be used for such purpose. It is prone to productivism or consumerism, over-valuing production and consumption of goods, and not reflecting improvement in human well-being. It also does not distinguish between money spent for new production and money spent to repair negative outcomes from previous expenditure. For example, it would treat as equivalent one million dollars spent to build new homes and one million dollars spent in aid relief to those whose homes have been destroyed, despite these expenditures arguably not representing the same kind of progress. This is relevant for example when considering the true costs of development that destroys wetlands and hence exacerbate flood damages. Simon Kuznets, the inventor of the concept of GDP, noted in his first report to the US Congress in 1934:the welfare of a nation can scarcely be inferred from a measure of national income. If the GDP is up, why is America down? Distinctions must be kept in mind between quantity and quality of growth, between costs and returns, and between the short and long run. Goals for more growth should specify more growth of what and for what.
List of countries by GDP (PPP)
GDP comparisons using PPP are arguably more useful than those using nominal GDP when assessing a nation's domestic market because PPP takes into account the relative cost of local goods, services and inflation rates of the country, rather than using international market exchange rates which may distort the real differences in per capita income. It is however limited when measuring financial flows between countries and when comparing quality of same goods among countries. PPP is often used to gauge global poverty thresholds and is used by the United Nations in constructing the human development index. These surveys such as the International Comparison Program include both tradable and non-tradable goods in an attempt to estimate a representative basket of all goods.