Sustainability rating systems for buildings: Comparisons and correlations

The issue of subjectivity in assigning weights for the domains and aspects in sustainability rating systems has not received much attention, and is hence explored in this study. A survey carried out among building construction sector professionals in a particular national context sought relative weights for various domains and aspects. Both direct ranking and analytic hierarchy process (AHP) methods were used. Reasonable agreement, with some differences, was found among architects, engineers and quantity surveyors on the relative weights for the six domains of Site, Energy efficiency, Water efficiency, Materials, Indoor environmental quality and Waste & Pollution; and also for the aspects. The overall domain weights were compared with those assigned in eight other rating systems, originating from eight different countries. While the Sri Lankan survey assigned the highest weight for the Site domain (with Energy efficiency a close second), in most other systems the Energy efficiency domain was top ranked. Relevant national indicators were chosen for 3 of the 6 domains, and the values of these indicators for the 9 countries were compared with the varying weights for the corresponding domains in the rating systems originating from those countries. Good correlation was found between the indicators and the weights.