Conceptual Critical Success Factors Model on Infrastructure Sustainability Rating System for California Construction Projects

This report addresses the sensitivity and reliability of the sustainability rating systems by comparing each category’s verified scores with its respective submitted scores to evaluate how points are awarded for infrastructure projects, examine which categories present the most challenges for verification, and identify the best category for verification in the sustainability rating system. The authors conducted three analyses using credit score data obtained from fourteen actual civil infrastructure projects certified under Envision. First, the Natural World category had the highest average score from the submitted and verified data. Pairwise comparisons using t-tests indicate that the mean value of one category does not differ statistically from that of other categories. Second, a one-way analysis of variance found no statistically significant differences among the five categories’ scores. Two-sample t-tests for comparing the submitted credit scores and the verified credit scores demonstrated no statistically significant difference in all five categories. However, the results showed that the verified credit scores are 18.63% lower than the submitted credit scores for all five categories. Third, multiple comparisons (Hsu’s MCB) showed that the Natural World category is the best category with 95% confidence. The results also indicated that the Quality of Life, Leadership, New World, and Climate and Risk categories have a higher possibility of being verified on a similar level, proving that those projects are close to the “best” category and present fewer challenges to be certified than the Resource Allocation category. The findings from this report will provide sustainability managers and project teams with insights into credit implementation in the pre-design stage of potential infrastructure projects that may pursue the certification process.