设计-建造和设计-招标-建造项目执行期成本控制绩效元分析

Metaanalysis on Cost Growth Gap between DesignBuild and DesignBidBuild Projects

摘要:

全面分析了对比设计建造（DB）和设计招标建造（DBB）项目执行期成本控制绩效的已有成果，发现各研究的样本项目条件不同，且大多为小样本，导致对两种模式下项目执行期成本控制绩效的差异缺乏一致结论.为此，采用随机效应元分析模型整合已有成果，基于大样本得出平均意义上的结论.结果表明，整体上DB模式能显著地改善执行期的成本控制绩效，稳健性检验说明该结果客观反映了两种模式的差异.分组元分析表明，DB模式在公共项目中带来的绩效改善较小；业主类似经验较少的项目中DB模式能更好地控制成本；DBB模式更适用于较复杂的项目；DB模式的绩效改善作用表现出先增后减的阶段性变化规律，与相应年代的政策导向有关.业主应在对比不同模式下项目绩效时充分考虑项目条件的影响，据此选择交易模式.得出的各项目条件对两种模式下成本控制绩效差异的影响在业主的交易模式选择决策中具有借鉴意义.

Abstract:

A thorough review of literature on DesignBuild (DB) and DesignBidBuild (DBB) project cost growth performance comparison indicates that existing studies focus on different types of projects, and most studies build on limited samples of projects. As a result, the conclusions of previous studies are diverse, and no general consensus has been reached on whether DB outperformed DBB in terms of cost growth. This paper employs random effect metaanalysis model to statistically integrate results in previous studies. Based on the integrated large sample, the gap between cost growth in DB and DBB projects is evaluated. The metaanalysis results, verified by the robust tests, show that DB projects achieve significantly lower cost growth on average. Further metaanalyses on different groups of studies reflect that DB system performs worse in public projects but better in unique projects. DBB is more conducive to cost growth control under complex project conditions. Cost growth improvements induced by DB system experienced growth initially, followed by shrinkage afterwards due to policy changes. This reminds clients that PDS should be selected according to specific project conditions. Hence, clients should consider both project conditions and performance history of different PDSs when selecting PDS. Clients may find this paper helpful in supporting their PDS selection decisions.