Finally, it will be noted that rather than using a multiplicity of indicators, one alternative solution might consist in synthesizing them in a single indicator. For example, the Human Development Index (HDI) worked out by the United Nations aggregates data regarding
health care, education, and national income to arrive at a worldwide classification of countries. Te ecologist and economist Tim Jackson has developed a Global Progress Indicator (GPI) combining, notably, environmental data with data concerning the national income and the latter’s distribution.