## 1 Introduction
Similar low certification levels were reported, and EA was again revealed as a category that moves a project from lower to higher certification levels. However, the LEED-NCv2.2 significantly differs from both the LEED-NC 2009 (v3) and the current LEED-NCv4 in at least two issues: (i) in the LEED-NCv2.2, the total number of points is 69, whereas, in the LEED-NCv3 and LEED-NCv4, the total number of points is 110; and (ii) all credits have the same weighting (1 pt) in the LEED-NCv2.2, whereas different weights are applied to different credits in the LEED-NCv3 and LEED-NCv4. Therefore, examining the LEED-NCv2.2 empirical evidence [6] to suggest new LEED versions seems inappropriate. However, when examining the LEED 2009 (which preceded the current LEED version 4), the empirical evidence is important because more similarities than differences are evidenced from the comparison of the LEED-NC 2009 and LEED-NCv4 categories, which are described below in chapter 1.2 (\"Comparing LEED-NCv3 with LEED-NCv4: similarities and differences\"). [PERSON] et al. [7] used significance tests to analyze the LEED-NC 2009 projects that were certified in several different countries (including the U.S.) for five years and pooled them into two unpaired groups (i.e., the LEED Silver level group and LEED Certified level group) in the same cluster. The sample sizes for both the Silver and Certified LEED certified projects were n\({}_{1}\) = 1310 and n\({}_{2}\) = 1201, respectively ([7], p. 375, Table 9) The authors concluded that EA, SS, and WE were the credits that moved the projects from a Silver to a Certified certification ([7], p. 375, Table 7). Consequently, if all LEED Silver and Certified levels projects around the world were considered in the same cluster, then the influence of other \"green building policies\" that are usually applied differently in different countries or states, such as ASHRAE 90.1 (Energy Standard for Buildings Except Low-Rise Residential Buildings), on the performance LEED projects was ignored [8]. This outcome can lead to a misinterpretation in LEED projects results [11]. Another design structure was presented in the [PERSON] and [PERSON] [8] study. The authors reported that the LEED-NC 2009 data were separately collected for each of ten U.S. states (CA, FL,GA, IL, MA, NY, OH, TX, VA, and WA) in 2016. Each state was defined as an individual cluster. In this context, it was suggested that \"any two LEED projects in the same state share more similar green building policy conditions compared to any two LEED projects from different states\" [11]. This logic design structure was based on the fact that U.S. energy regulation, such as ASHRAE 90.1, is regulated at the state (i.e., not national) level; therefore, different states adopted different versions of ASHRAE [12]. In this respect, it was shown that the ASHRAE 90.1 version can influence the results of the LEED Silver-to-Certified certifications [8]. Thus, the following three different strategies of certified projects in transition from Silver to Certified were revealed (a) EA-emphasized (e.g., California), (b) SS/EQ-emphasized (e.g., New York), and (c) integrated (e.g., Georgia) strategies [8]. At least one international LEED-NC 2009 application suggested by [PERSON] et al. [13] was recognized throughout the literature. The authors studied LEED-NC 2009 certified projects in China (172 projects), Turkey (86 projects), and Brazil (75 projects) [13]. It was reported that significant differences among the countries were revealed in LEED categories, including SS, WE, EA, EQ, and ID. However, in their study, [PERSON] et all. [13] pooled all projects from all certification levels (certified, silver, certified, and Platinum) into one total sampling pool. Such a comparison of the LEED categories' achievements among countries [13] is not appropriate because each of the countries had different numbers of certified, silver, Certified, and Platinum projects. In this study, an additional international LEED-NC 2009 application was examined.