Bias versus error: why projects fall short

Worldwide, major projects often make the headlines as they suffer from a fourfold whammy of delays, cost blowouts, benefit shortfalls and stakeholder disappointments. It seems that error and bias can explain their underperformance. Which overarching explanation outweighs the other? It is the question this paper aims to address.

Insights are garnered from decades of research on thousands of major projects in developed and developing countries worldwide. In particular, two high-profile project cases, the Veteran Affairs Hospital in Aurora, Colorado (USA) and the Philharmonie de Paris (France), are explored.

The case projects show that error and bias combine to best explain project (under) performance. Applying best practices or debiasing project cost and benefit estimates is insufficient to prevent cost blowouts and benefit shortfalls. The confrontation of the two overarching explanations is not merely platonic. It is real and may lead to a media and legal battle.

This viewpoint calls practitioners to transcend the error versus bias debate and reconcile two key characters in the world of major projects: the “overoptimistic” who hold a bias for hope and firmly believe that, despite error down the road, many projects would, in the end, “stumble into success” as creativity may come to the rescue; and the “overpessimistic” who hold a bias for despair and think many projects should not have been started.