With a compound annual growth rate of 5.69%, the modular construction market is forecasted to increase to a market value of $154.8 million by the end of 2023. Traditional stick-built construction and modular construction differ in many aspects including design, engineering, collaboration requirements, logistics, and others. Available research efforts tried to study and model the complex modular construction processes. However, they seemed to fall short in investigating modular construction processes in a comprehensive and holistic manner. In effect, the currently used decision-making models and processes for modular construction do not necessarily reflect the diverse and multiple interconnected and associated factors. This paper develops a comprehensive list of decision factors as well as determines future research needs for modular construction. As such, the authors (1) conducted a systematic literature review and analysis of modular construction studies that were conducted between 2009 and 2019, (2) highlighted the broad factors affecting decision-making in modular construction projects, and (3) utilized social network analysis (SNA) to quantitatively identify the literature gaps and strengths and create a roadmap for the factors that need further investigation. This paper identified 50 decision factors affecting the various modular construction operations in the construction industry. Consequently, it was revealed that there are some understudied decision factors, including those related to legal and regulatory considerations, material and construction waste management, green practices, as well as commissioning and testing. Further, it was shown that there is an explicit absence of the decision models and frameworks that simultaneously incorporate all the identified decision factors. Accordingly, this study provides a substantiated foundation for comprehensive decision-making processes for modular construction.