# An Investigation of the Selection of LEED Version 4 Credits for Sustainable Building Projects
## 4 Results  
The PAS means, standard deviations, and results of the Kolmogorov-Smirnov test and one-sample \(t\)-test are presented in Table 2. As the Kolmogorov-Smirnov test results confirmed that the data collected displayed significant differences with a normal distribution, the one-sample \(t\)-test was only performed for the sample as a whole (number of samples \(>\) 30) in the next step; the results are also presented in Table 2. A one-sample \(t\)-test was conducted to identify the significantly awarded credits \begin{table}
\begin{tabular}{c c c} \hline \hline
**Purpose** & **Method** & **Software** & **References** \\ \hline To determine the order of the accessible LEED v4 credits. & Mean/SD-Value & MS Excel & [10; 34; 35] \\ To test the normality of the data. & Kolmogorov–Smirnov & SPSS 20.0 & [1; 10; 40; 41; 42] \\ To determine whether the credits are & & \\ significantly achieved. & One-sample \(t\)-test & SPSS 20.0 & [1; 40; 41; 42] \\ To compare the two unpaired groups and conduct a & Wilcoxon–Mann–Whitney & SPSS 20.0 & [1; 10; 42] \\ sacrificial pseudoreplication analysis. & [PERSON]’s \(\delta\) \& & MS Excel & [1; 40; 42] \\  & neo-Fisherian & & \\ To assess the achievement of two related credits. & Association rules & R & [19; 22; 41] \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The analytical methods used in the study. at LEED projects with a comparative value of 50% and a confidence index of 95%. The results of the one-sample \(t\)-test and PAS mean value showed that the following credits (see the Appendix A for a list) were significantly achieved in the LEED v4 projects: INc2 (LEED accredited professional), IEQC3 (construction IAQ management plan), LTc2 (credit sensitive land protection), MRc5 (construction and demolition waste management), WEc1 (outdoor water use reduction), WEc4 (water metering), SSc5 (heat island reduction), SSc1 (site assessment), INc1 (innovation), WEc2 (indoor water use reduction), IEQC1 (enhanced IAQ strategies), EAc2 (optimize energy performance), LTc7 (credit reduced parking footprint), IPC1 (integrative process), EAc3 (advanced energy metering), SSc6 (light pollution reduction), SSC3 (open space), LTc8 (credit green vehicles), and EAc1 (enhanced commissioning). Perhaps not surprisingly, the most popular awarded credits (CAD > 80%) were those with the lowest cost [1], including policy-related credits such as INc2 (LEED accredited professional), IEQC3 (construction IAQ management plan), LTc2 (sensitive land protection), and MRc5 (construction and demolition waste management), as well as those related to water efficiencies, such as WEc4 (water metering) and WEc1 (outdoor water use reduction). In particular, the fact that LTc1 (neighborhood development location) credits have a zero PAS value suggests that as currently implemented, the USGBC's LEED Neighborhood Development program is not achieving the desired results. To award and encourage more effort of green building developers, the USGBC provides four levels of LEED certification: LEED Certified, LEED Silver, LEED Gold, and LEED Platinum [1]. LEED Gold and LEED Platinum bring a significantly greater market value [43], but also require greater investment from developers as they involve a more complex design/construction to satisfy the requirements of the higher certification levels. This led us to investigate the choices made by developers faced with this decision, focusing on a comparison of the credit allocations between projects achieving two adjacent LEED levels utilizing the results of the Wilcoxon-Mann-Whitney (WMW) test and [PERSON]'s delta values (Table 3).