Information integration is considered a source of competitive advantage in the capital projects industry. While it has been broadly implemented, many organizations appear to have achieved only limited benefits from their efforts. This dissertation investigates the complementarity relationship between information technology (IT) use and project execution processes and practices. It asserts that rather than directly improving an organization’s competitive advantage, IT serves instead as a mode to improve existing processes and practices which in turn serve to improve the bottom line. Building from this foundation, the dissertation proceeds to expand its findings to document mechanisms by which various resources influence the complementarity relationship. Topics within this dissertation are investigated with both quantitative and qualitative approaches. Using capital projects data, evidence of complementarity is established quantitatively between general use of IT and best practices. The benefits of complementarity in terms of cost, schedule, and rework project performance measures are documented. Data analyses show that more use of IT is associated with more use of best practice; and, projects that intensively implement IT and best practice tend to show superior project performance. Furthermore, by investigating the use of a specific technology, this dissertation presents a thorough statistical analysis showing that IT use affects the use of practices, which together support improved project performance. Next, this dissertation lists organization resources that may affect complementarity. Using sixteen actual information integration cases, the major resources consistently affecting complementarity are identified. Illustrations of seven case studies present how the resources are managed. The case studies are also used when discussing the interaction of IT use and processes generating complementarity.The primary contribution of this research is to provide a quantitative evidence of IT’s indirect impact on construction project performance via practices. A broad discussion citing the range of resources affecting the complementarity and identifying the major ones in the capital projects industry is another contribution of this research.