LEED is an acronym for Leadership in Energy and Environmental Design, the council's rating system for measuring the effectiveness of environmentally efficient buildings. LEED ranks buildings on a 100-point scale measuring energy and atmosphere, the sustainability of a site, efficient use of water and the use of environmentally responsible materials and resources in the building's construction and maintenance. It also awards six points for innovative design and four points for embracing regional priorities in products and services. The resulting levels are Certified (40 to 49 points), Silver (50 to 59 points), Gold (60 to 79 points) and the greenest category, Platinum (80 points or more).