## 3 Results
### Indoor Environmental Quality  
Figure 7 shows the boxplot and [PERSON]'s \(\delta\) results in the EQ category. According to the boxplot, the median increased from Certified through Silver and Gold to Platinum (5, 7, 7, and 9 achieved points, respectively) with approximately the same wide range in Certified, Silver, Gold, and Platinum (1-9, 2-10, 4-8, and 7-13 achieved points, respectively). According to [PERSON]'s \(\delta\), the EQ category demonstrated low achievement in all four certification levels. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Credit**} & \multirow{2}{*}{**Possible**} & \multicolumn{4}{c}{**Achieved Points**} \\ \cline{3-6}  & & **Certified** & **Silver** & **Gold** & **Platinum** \\ \hline Building life-cycle impact reduction & 5 & \(0.0\pm 0.0\) & \(0.0\pm 2.0\) & \(0.0\pm 2.8\) & \(3.0\pm 0.8\) \\ \hline BPD \& O–environmental product declarations & 2 & \(0.0\pm 1.0\) & \(1.0\pm 1.0\) & \(1.0\pm 1.0\) & \(1.0\pm 0.3\) \\ \hline BPD \& O–sourcing of raw materials & 2 & \(1.00\pm 0.0\) & \(0.0\pm 0.0\) & \(0.0\pm 0.8\) & \(1.0\pm 1.3\) \\ \hline BPD \& O–material ingredients & 2 & \(1.00\pm 0.0\) & \(1.00\pm 1.0\) & \(1.00\pm 1.0\) \\ \hline Construction and demolition waste management & 2 & \(1.00\pm 0.0\) & \(2.0\pm 0.0\) & \(2.0\pm 0.8\) & \(2.0\pm 0.3\) \\ \hline \multicolumn{6}{l}{Notes: Effect size is considered to be: very high if \(|\delta|<0.147\) (bold font), high if \(0.147<|\delta|<0.33\) (bold italic font), medium if \(0.33<|\delta|<0.474\) (italic font), and low if \(|\delta|\geq 0.474\) (normal font).} \\ \end{tabular}
\end{table} 
Table 6: Credit points achieved for Materials and Resources category of LEED-NCv4 projects: median \(\pm\) IQR (25 th–75 th) and Cliff’s \(\delta\) effect size between possible and achieved points in a credit. Figure 6: The boxplot results and Cliff’s \(\delta\) effect size between possible and achieved points in the Materials and Resources (MR) category. Effect size is considered to be: very high if \(|\delta|<0.147\) (bold font), high if \(0.147<|\delta|<0.33\) (bold italic font), medium if \(0.33<|\delta|<0.474\) (italic font), and low if \(|\delta|\geq 0.474\) (normal font). Table 7 provides median \(\pm\) IQR (25 th-75 th) and Cliff's \(\delta\) results for EQ credits. In the four certification levels, five of the nine EQ credits had similar Cliff's \(\delta\) effect sizes between possible and achieved points. Among these credits, only the Construction indoor air quality management credit had high or very high achievement, whereas the Low-emitting materials, Indoor air quality assessment, Daylight, and Acoustic performance credits had low achievement in each level of certification. Low-emitting materials requires the use of special interior materials and products such as paint, coverings, flooring, and furniture with low volatile organic compound (VOC) emissions [5], which might increase the project budget. Indoor air quality assessment requires cleaning the indoor air in buildings after construction and during occupancy. Daylight credit is related to window area, which can be restricted by other design requirements, such as an esthetics. Acoustic performance requires restricting background noise levels of mechanical systems [5]. Four other EQ credits had different Cliff's \(\delta\) effect sizes between possible and achieved points in the different certification levels (Table 7). Enhanced indoor air quality had low achievement in Certified and Silver projects and medium in Gold and Platinum projects. Thermal comfort and Interior lighting had low achievement in Certified, Silver, and Gold projects, and high or very high in Platinum projects. The Quality views credit gradually increased from low-achieved in Certified and Silver projects to medium in Gold projects and high in Platinum projects. Enhanced indoor air quality requires increased ventilation rates and installation of filtration systems [5].