Despite past and present research on planning and delivery methods, the construction industry is still characterized by endemic cost and schedule overruns that are often accompanied by disclosures of actual performance late in the project delivery. As a response to such major shortcoming, this study investigated the novel and undocumented practice of validation. The purpose of project validation is to prove or disprove whether the project team can successfully deliver a project that satisfies the owner's business case and scope within the constraints of cost and schedule. In order to document validation, this study leveraged a multiple case study analysis of remarkable project validation efforts. Data were collected through open-ended phone interviews with eight subject matter experts. Each expert was requested to share validation aspects such as information inputs and outputs, team and culture, steps, or approval solicitation. The interviews were complemented with the authors' first-hand observations at validation sessions. Qualitative analysis of the collected data enabled the detail of the benefits, nuances, and steps for a successful validation effort. Validation is executed within a short duration, limited budget, and little or no design. Validation culminates in an informed decision by the owner on whether to authorize (go) or not to authorize (no-go) the project. When the project is authorized, the owner and the team contractually agree to the project based on the shared commitment that the success criterion can be met. Alternatively, a no-go decision enables the owner to allocate the project funds into alternative investments that can meet the owner's objectives and provide the expected rate of return.