The current inability to timely ascertain cost and schedule outcomes in construction projects is highly detrimental to a construction industry characterized by endemic deviations. This study hypothesizes that organizational behaviors have a strong effect on the team’s ability to generate accurate cost and schedule predictions early, as opposed to late, in the project delivery process. A mixed-method research approach sequentially combined nonparametric statistical analyses of survey responses to quantify the influence of behaviors on predictability and research charrettes with subject matter experts to assess the findings and characterize practical applications. Multiple behavioral factors, such as those associated with the design of incentives or the reporting environment, were documented to have a significant effect on predictability. This study contributes with a novel combination of behavioral and predictability focus to the body of knowledge in forecasting. Such knowledge has been constrained within the silo of estimating techniques and, hence, without the consideration of behaviors and their impact on timeliness.