“…The main idea is to monetise non-monetary aspects of welfare such as leisure, domestic production, health and education, which are seen as investments that guarantee the sustainability of current standards of living. Later, in the same spirit, Daly & Cobb (1989) introduced the costs of environmental degradation, paving the way for a new generation of indicators known as "green GDP", such as the "Genuine Progress Indicator" (Cobb & Cobb, 1994). This second line of indicators could be described as semitheoretical, since it relies on economic theory for the principles but does not use it more for the actual construction of indicators.…”