## 1 Introduction  
Currently, green building certification is a common approach to building in a sustainable way. Due to the differing existing environmental, political, economic, social, and technological contexts of different countries, it is accepted that appropriate green rating systems can be developed for specific countries. However, some country-specific systems have also received much attention in foreign countries; the most prominent example of such a foreign-accepted system is Leadership in Energy and Environmental Design (LEED). This system was initially developed (in 1998) in the U.S. by the U.S. Green Building Council (USGBC), a non-profit coalition of the building industry [1]. It should be noted that LEED was built as a measure of sustainability. According to [2], sustainability should encompass environmental sustainability, economic sustainability, and social sustainability. In this respect, [PERSON] et al. [3] analyzed LEED sustainability aspects and confirmed that 83% of the credits are related to environmental sustainability, 16% of the credits deal with social sustainability, and 1% of the credits refer to economic sustainability. Similar results were presented by [PERSON] et al. [4], who concluded that LEED devotes 74.59%, 18.03%, 0.82%, and 6.56% of credits to environmental sustainability, social sustainability, economic sustainability, and others, respectively. However, LEED is still named as the most popular green rating system in the world [1]. According to [PERSON] and [PERSON] [1], the first version of LEED (LEEDv1) was designed for new building and included a simple list of sixteen credits (for example, Indoor Air Quality with 85% air filtration, Temperature according to ASHRAE 55-1992, Energy Conservation according to ASHRAE 90.1-1989), while four of the credits (for example, Waste Disposal and Smoking Ban) were mandatory. Each of the credits was awarded one point. Next, LEEDv2, which was launched in 2000, divided credits into five categories (Land, Water, Energy, Materials, and Indoor Environmental Quality). LEEDv2 was a turning point to further expand the LEED system to different building types: LEED-NCv2.2,LEED-C&S, LEED-EB, LEED-CI, and Homes, for newly constructed buildings, core and shell buildings, existing buildings, commercial interiors, and homes, respectively, were introduced in 2004 and 2005. LEED-NCv2.2 consisted of six categories [1]--Sustainable Sites (SS, 14 points), Water Efficiency (WE, five points), Energy and Atmosphere (EA, 17 points), Materials and Resources (MR, 13 points), Indoor Environmental Quality (EQ, 15 points), and Innovation and Design Process (IN, 5 points)--summing to 69 points in total. Four certification levels--Certified (26-32 points), Silver (33-38 points), Gold (39-51 points), and Platinum (52-69 points)--were introduced. However, the credits were still weighted equally (one point to each credit). The next version, LEED-NCv3, was introduced in 2009 [1]. This version included seven categories: SS (26 points), WE (10 points), EA (35 points), MR (14 points), EQ (15 points), IN (6 points), and Regional Priority (RP, 4 points), awarding a total of 110 points. Each of these categories had several prerequisites (which were mandatory for performance) and credits (which were selective for performance). In this version, credit weighting was introduced, awarding a different number of points to different credits, according to their importance in the environmental influence. In addition, the following certifications were suggested: Certified (40-49 points), Silver (50-59 points), Gold (60-79 points), and Platinum (80 points and above). The current version, LEED-NCv4 that was introduced in 2013 [1], is very similar to the previous LEED-NCv3. It also awards 110 points in total. However, this version has nine categories: Integrative Process (IP, one point), Location and Transportation (LT, 16 points), SS (10 points), WE (11 points), EA (33 points), MR (13 points), EQ (16 points), IN (6 points), and RP (4 points).