Predictability index: Novel metric to assess cost and schedule performance

The ability to timely forecast accurate project outcomes is fundamental in an industry marked by endemic cost and schedule deviations. Indeed, owners and contractors alike make key strategic decisions about individual projects and capital investment programs alike based on forecasted values. As a departure from current cost and schedule assessments solely based on deviations at completion, this article introduces the Predictability Index, a novel performance metric that also considers the project team's ability to timely predict outcomes at completion. This article conceptually explains and defines the index and, based on the statistical analysis of retrospective data from 135 completed projects, identifies threshold values of predictability performance. Complementary, lessons learned and observations collected from the adoption and assessment of predictability by industry organizations are also discussed. A significant cultural shift within an organization is necessary for project teams to focus on predictability performance.