� 2019 Canadian Society for Civil Engineering. All rights reserved. A construction project is considered to be unique due to the process of delivering a customer-designed product, diverse stakeholders involved, the unique location and timeframe of construction, and specific social, economic, and environmental constraints attached to it. The uniqueness of construction projects brought great challenges to the construction industry professionals as well as researchers and educators in the construction discipline. If a method or a model can be developed to assess the similarity between projects and make project comparison more science than art, we can increase the confidence level of researchers when they conduct analyses and make conclusions. We can help industry professionals make better decisions by providing more accurate information. This paper introduces the concept of Foundational Attributes of construction projects. A literature review is conducted to create the framework, and case study projects are applied to the framework to demonstrate how this concept helps with project comparison. A spider chart is chosen to host the concept of Foundational Attributes, and two case study projects are selected to demonstrate how to quantify project similarity using the concept of Foundational Attributes and a spider chart. Last but not least, lessons learned and future research directions are discussed at the end of this paper