One of the primary objectives of this research was the development of construction sustainability metrics. Such metrics can help project teams assess their sustainability implementation efforts or measure performance against set targets. They can also measure sustainability implementation progress over time. In general, metrics come in one of two forms: input-oriented and output-oriented metrics.
- Input metrics typically measure the breadth and/or extent of effort applied in the pursuit of an established goal.
- Output metrics focus on the actual achievement of one or more performance goals.
RT-304 developed the CPSA Implementation Index, an input metric, as a numerical measure of the breadth and extent of a project’s implementation for all 54 CPSAs. (RS304, p. 27 or IR304-2, p. 33)
The table below shows the points the Index awards each of the 54 CPSAs, depending upon the extent of its implementation on the project.
Performance-oriented output metrics are generally preferable to resource- or process-oriented input metrics, and the research team identified a wide range of construction sustainability output metrics. Following are the 7 most predominant output metrics: (RS304, p. 28)
- Percentage of projects with sustainability performance section in project reports
- Cost savings
- Portion/volume of total waste recycled or diverted from a landfill
- Street value of recycled material
- Equipment environmental performance
- Size of carbon footprint from project
- Number of complaints from community, agency, or camp residents