Comparison of Preproject Planning for Green and Conventional Buildings

摘要

The importance of green buildings has been frequently highlighted. However, barriers such as greater complexity, lack of understanding of sustainability, and the perception of a greater possibility of cost overrun have hindered the dissemination of green buildings. More planning efforts for green buildings can presumably help mitigate these barriers. This paper investigates preproject planning efforts for green and conventional building projects. Project-level data were collected (124 in total, 71 from conventional building projects and 53 from green building projects), with project data consisting of general information about the project, a Project Definition Rate Index (PDRI) survey, and cost performance. The project data were categorized into four groups based on their project type (green and conventional) and cost performance (actual cost on/under budget and over budget). For the four groups, a two-way analysis of variance test was used to compare the degree of preproject planning efforts measured by PDRI. The analysis indicated that green projects tend to have more investment in preproject planning efforts than conventional projects, and the difference was marginally statistically significant at the level of α = 0.05. In addition, a comparison of the mean PDRI values of the four groups revealed that green projects with a superior cost performance invest more in preproject planning efforts than other groups, and the difference was statistically meaningful. From the interaction effect, we also found that the impact of preproject planning on cost performance is more critical for green projects than for conventional projects. Regarding the preproject planning category, we found that green projects with superior cost performance tend to involve more planning with regard to business strategy, project requirements, site information, building programming, and building/project design parameters. These findings make two contributions. First, the findings help practitioners justify additional preproject planning efforts for green projects. Second, some of the results of this study will be useful to practitioners initiating sustainable projects by helping with the determination of which aspects of green buildings should involve more extensive planning. These findings will help reduce the possibility of cost overruns and allow more green projects to be deployed in order to address the need for sustainability.