CASBEE (Comprehensive Assessment System for Building Environmental Efficiency) is a certification system especially designed for the Japanese market, and beyond it, for the Asian market. It was introduced in 2001 and has been regularly developed further and updated since. To date, over 500 certificates have been issued ( certificationE.htm). CASBEE particularly considers the aptitude of buildings for their local conditions in Japan, e.g. regarding seismic safety.

One distinctive feature of the system is that the points for the assessment of building quality and required expenditure are summed up separately, in order to calculate their quotient.

Thus, the measure represents the actual efficiency of the step on a formal/mathematical level, meaning the ratio of the result achieved to the expenditure required for it.