Relationship between Project Space Types, Optimize Energy Performance Credit, and Project Size in LEED-NC Version 4 (v4) Projects: A Case Study

A previous study (Pushkar 2021) showed a significant non-parametric correlation between the Optimize Energy Performance credit from the energy and atmosphere category (EAc7) and project size in Leadership in Energy and Environmental Design for New Construction and Major Renovations version 4 (LEED-NC v4) office space projects. However, in such an empirical analysis, there are at least two problems: the choice between parametric and non-parametric statistics, and the choice between the Wilcoxon–Mann–Whitney (WMW) and analysis of covariance (ANCOVA) non-parametric tests. This study aims to evaluate EAc7 credit achievement for different types of spaces in LEED-NC v4 projects. We show that, in order to evaluate the differences between two LEED data groups, (1) a non-parametric procedure is preferable to a parametric one, and (2) if there is Spearman’s correlation between EAc7 credit achievement and project size for the same LEED-NC v4 project, then Quade’s ANCOVA is preferable to WMW. The results of these tests show that, in two out of three cases, office space projects had better EAc7 credit achievement than higher-education spaces at the gold certification level and public assembly spaces at the silver certification level.