Leed-Ncv3 Silver and Gold Certified Projects in the Us: An Observational Study

Abstract

The Leadership in Energy and Environmental Design (LEED) rating system has been widely used in the US. However, until now, there has been no clear understanding of the strategies that should be used to make the transition from Silver to Gold certified projects. The aim of this study was to determine the trends in certified projects for both Silver and Gold LEED for New Construction and Major Renovations (LEED-NCv3) in 2016. Three performances, including (i) certification, (ii) category/subcategory/sub-subcategory certification, and (iii) cross-certification, were evaluated for both Silver and Gold LEED-NCv3 certified projects. For an ordinal measurement scale, a two-tailed Mann-Whitney U test was used. For a ratio measurement scale, an unpaired two-tailed t-test was used. If eight or more Silver and Gold certified projects occurred in the same state, then the state was selected for statistical analysis. As a result, ten states were selected. The following was revealed: (i) low certification performances for both Silver and Gold; (ii) high category performance for Sustainable Sites and Innovation in Design and low category performance for Energy and Atmosphere for both Silver and Gold projects; and (iii) three different strategies of certified projects in transition from Silver to Gold that include (a) energy-emphasized (e.g., CA), (b) non-energy-emphasized (e.g., NY), and (c) integrated (e.g., GA) strategies. We speculate that the possible reasons for such deviations in the decision strategies were due to differences between the adopted ASHRAE 90.1 standards (ASHRAE Standard 90.1 2007 or ASHRAE Standard 90.1 2010) in each of the states.

Sacrificial Pseudoreplication in LEED Cross-Certification Strategy Assessment: Sampling Structures

“…It was originally defined in the context of manipulative experiments but can also occur in observational studies" [3]. Leadership in Energy and Environmental Design (LEED)-certified projects data analysis is an observational study [4]. Therefore, LEED project data analysis should be considered regarding the problem of pseudoreplication.…”

“…A collection of Certified, Silver, Gold, and Platinum LEED-certified projects in the US Green Building Council (USGBC) website [10] is a unique database that has been used by researchers to perform retrospective analyses of the LEED-certified building certification, category, and cross-certification performances [4,8,9,11,12]. Such analyses produce feedback that can be a useful information for experts who oversee further improvements in the seven LEED categories such as sustainable sites (SS), water efficiency (WE), energy and atmosphere (EA), material and resources (MR), indoor environmental quality (EQ), innovation in design (ID), and regional priority (RP).…”

“…In three recent cases [4,8,9], a single-unit design structure of the analysis according to the term originally suggested by Hurlberd [7] (p. 652) was used. In these studies, all LEED projects were treated as statistically independent units using a non-parametric Wilcoxon-Mann-Whitney (WMW) test [13].…”

“…In this respect, Pushkar and Verbitsky [4] more recently performed pooling of all LEED projects within individual states to determine cross-certification performances of Silver-Gold LEED-NCv3 certificated projects in 10 US states (CA, n 1 = 42, n 2 = 58; FL, n 1 = 31, n 2 = 11; GA, n 1 = 11, n 2 = 9; IL, n 1 = 13, n 2 = 19; MA, n 1 = 19, n 2 = 14; NY, n 1 = 14, n 2 = 11; OH, n 1 = 23, n 2 = 8; TX, n 1 = 27, n 2 = 9; VA, n 1 = 38, n 2 = 11; WA, n 1 = 10, n 2 = 11) in 2016. It should be noted that because LEED data is ordinal data, the median credit increase (MdCI) in the Pushkar and Verbitsky [4] was used instead of the mean credit increase (MCI) that was suggested in the Wu et al [9] study.…”

“…It should be noted that because LEED data is ordinal data, the median credit increase (MdCI) in the Pushkar and Verbitsky [4] was used instead of the mean credit increase (MCI) that was suggested in the Wu et al [9] study. In particular, the EA category was propelled in six of 10 [4].…”