## 1 Introduction
The LEED-NCv2.2 categories were: Sustainable Sites (SS), with 14 possible points; Water Efficiency (WE), with five possible points; Energy and Atmosphere (EA), with 17 possible points; Materials and Resources (MR), with 13 possible points; Indoor Environmental Quality (EQ), with 15 possible points; and Innovation and Design Process (IN), with 5 possible points. The projects certified under this version were studied by [PERSON] [12] and [PERSON] et al. [13]. [PERSON] [12] analyzed over 2000 LEED-NC, LEED-CI, LEED-C & S, and LEED-EB certified projects registered as of March 2009 in the U.S. The analyzed LEED versions were not reported by [PERSON] [9]. However, according to the publishing date of this study, versions 1-2.2 were likely considered. [PERSON] [12] only reported the achievements of the total number of LEED points (i.e., certification achievements), claiming that these were low. In particular, most of the projects received certification with a total number of points only slightly above the bottom thresholds for each certification level (26, 33, 39, and 52 for Certified, Silver, Gold, and Platinum, respectively). [PERSON] et al. [13] analyzed the category achievement of 5340 LEEDv2.2 projects around the world including the U.S., reporting varied achievements. In particular, the analysis of all projects together demonstrated that the IN category achievement was high (80.1% of possible points), the SS, WE, and EQ category achievements were intermediate (57.3-68.9% of possible points), and the EA and MR category achievements were low (42.6-43.4% of possible points). A comparison between two adjacent certification levels (Silver vs. Certified, Gold vs. Silver, and Platinum vs. Gold), i.e., cross-certification analysis, revealed that from level to level, EA category achievement increased considerably, SS and EQ category achievements showed intermediate increases, and WE, MR, and IN category achievements showed low increases. The next version, LEED-NCv3 [14], was reshaped to include 110 points in total. As a consequence, the available points became 26, 10, 35, 14, 15, and 6 for SS, WE, EA, MR, EQ, and IN categories, respectively. Thus, the EA category, which had low achievements in projects certified under the previous LEED-NCv2.2 [13], was enhanced in LEED-NCv3, suggesting 19 possible points instead of the previous 10. However, the MR category, which also had low achievements in projects certified under LEED-NCv2.2 [13], remained the same as in the previous version. Different weights were applied to the different credits. For example, in the SS category, the Alternative transportation-public transportation access credit included six possible points, whereas Alternative transportation-low-emitting and fuel-efficient vehicles had four possible points. A new category, Regional Priority (RP) credit,with four bonus points, was first introduced in LEEDv3 [14] to encourage solving U.S. regional environmental issues. The certification and category analysis of projects certified under LEED-NCv3 were extensively studied by [PERSON], et al. [15] and [PERSON] and [PERSON] [16; 17]. [PERSON], et al. [15] studied 3416 LEED-NCv3 certified projects worldwide, including the U.S. The analysis of all projects together demonstrated that the SS, WE, EQ, and IN category achievements were intermediate (59.1-69.8% of possible points), and the EA and MR category achievements were low (40.3% and 38.7% of possible points). The cross-certification analysis of LEED-NCv3-certified projects confirmed the results previously reported by [PERSON] et al. [13] for projects certified under LEED-NCv2.2. In particular, from level to level, EA category achievement showed considerable increases, the SS and EQ category achievements showed intermediate increases, and the WE, MR, and IN category achievements showed low increases. [PERSON] and [PERSON] [16] studied 920 projects certified Silver and Gold under LEED-NCv3 in 10 states in the U.S. (California, Florida, Georgia, Illinois, Massachusetts, New York, Ohio, Texas, Virginia, and Washington) in 2016.