Comparison of OSC (Off-Site Construction) Level Measurement Methods

Studies have shown that the implementation of OSC (off-site construction) is beneficial. However, most studies have relied on simulated project data to forecast the potential advantages of OSC, often using surveys or expert consultations as their primary research methods. Others have based their analyses on a specific sample size, focusing on cost savings and reduced construction time. Such approaches inherently possess limitations. In this study, we define "OSC level measurement" as the comprehensive process of quantifying the application of OSC elements throughout the project lifecycle. Numerous studies have proposed methods for OSC level measurements. However, they vary in their applicability to different facility types and project phases and employ country-specific quantification items and methods. These variations complicate the comparison or integration of OSC measurement methods on an international scale. The comprehensiveness of the representations in the existing industry foundation classes (IFCs), which is required to carry out automated OSC level measurement, is not yet investigated. This study aimed to systematically compare and analyze various methods for measuring OSC levels in construction projects. We intend to provide researchers and professionals with the necessary characteristics and requirements to develop standardized OSC level measurement methods in the future. The key takeaways emphasize the need for establishing the necessary standardization of the list of OSC elements, creating a framework for standardized quantification items using IFC elements based on BIM data to measure the extent of OSC elements' application, and unifying the quantification methods for assessing the proportion of OSC elements. Ultimately, this standardization will pave the way for more informed decision making, innovation, and the implementation of sustainable solutions in the construction industry.