## Materials and Methods  
### Comparing the LEED-NCv3 with LEED-NCv4: Similarities and Differences  
In this empirical study, the focus was on the LEED-NC 2009 (version 3), one version before the current LEED-NC version 4. This approach is due two reasons: (i) availability of a sufficient sample size of LEED 2009 projects certified in Finland, Sweden, Turkey, and Spain in the US Green Building Council (USGBC) project directory, and (ii) the LEED-NC 2009 and LEED-NCv4 still share more similarities than differences. (i) Currently (31 July 2018), according to the USGBC site, analyzing LEED-NC 2009 certified projects (four certification levels: certified, silver, Certified, and Platinum) revealed 30 certified projects in Finland, 38 in Sweden, 218 in Turkey, and 74 in Spain [14]. However, when considering projects certified with the LEED-NCv4, Finland has one certified project and one project with a \"Certification in progress\" status, Sweden has zero certified projects and zero projects with \"Certification in progress\"statuses, Turkey has zero certified projects and 14 projects with \"Certification in progress\" statuses, and Spain has zero certified projects and two projects with \"Certification in progress\" statuses [14]. (ii) Comparing the LEED-NC 2009 and LEED-NCv4 rating schemes, in general, the following should be noted: the total number of points is the same (110 pts), and the number of points in each category is very similar (Table 1). In particular, the SS category in the LEED-NCv4 was split into Location and Transportation (LT) and SS categories. In the LEED-NC 2009, the SS category includes land usage, green transportation and parking, site usage and rainwater, heat island, and light pollution reductions. In the LEED-NCv4, the LT category includes land usage and protection and green transportation parking, while the SS category includes site usage and protection and rainwater, heat island, and light pollution reductions. In fact, the assessment of SS issues is very similar to the assessment of LT+SS issues. The WE category was expanded in the LEED-NCv4, including, in addition to indoor and outdoor water reduction (that were presented in LEED-NC 2009), requirements concerned with the conservation of water used for cooling towers and installation of a water consumption metering system. However, in both versions, the indoor and outdoor water reductions have similarly high weights: 8 pts from the total 10 pts in the LEED-NC 2009 and 8 pts of the total 11 pts in the LEED-NCv4. In the EA category, the issues of the LEED-NC 2009, such as energy optimization and metering, enhanced commissioning and refrigerant management, and renewable and green energy production are still relevant in the LEED-NCv4. In general, similar weighting is applied to these energy concerns. In particular, the most important energy optimization credit has almost the same weight in both versions: 19 pts of the total 35 pts in the LEED-NC 2009 and 18 pts of the total 33 pts in the LEED-NCv4. Only the weight of enhanced commissioning was increased in LEED-NCv4; 6 pts versus 2 pts in LEED-NC 2009. The MR category in the LEED-NCv4 has newly introduced a life cycle impact reduction credit for building and material optimization and reusing, which has a high weight of 5 pts in the total 13 pts. Additionally, the direct requirements concerning building reusing and material recycling that were presented in the LEED-NC 2009 were reformulated in the LEED-NCv4, requiring manufacturers' declarations regarding the source and production of raw materials, building materials and components to be disclosed. However, the issues of concern are still the same in each version, namely, building material reuse and recycling and construction waste management. In general, the EQ category in the LEED-NCv4 considers issues that were of concern in the LEED-NC 2009: construction and indoor air quality, low-emitting materials, thermal comfort, and interior lighting and daylight with quality views consideration.