Schedule delays of major projects: what should we do about it?

ABSTRACT

Cost overruns and schedule delays are one of the most common reasons for project failure. Although schedule delays not only result in significant financial implications to project sponsors but also lead to substantial social costs to the public, scant attention has been dedicated to schedule delays [Padalkar, M., & Gopinath, S. (2016). Six decades of project management research: Thematic trends and future opportunities. International Journal of Project Management, 34(7), 1305–1321]. This study therefore investigates the frequency, magnitude, and characteristics of schedule delays occurring during the construction of 113 large public procurements built in the U.S. and the U.K. between 1999 and 2018. Through tests of hypotheses, this study finds that there is a gap between presumptions and reality. Although extensive efforts were made to project controls in the U.S. and the U.K. over the last two decades, this study also finds that project performance has not improved at all from a schedule perspective. In order to address the issue, this study then suggests reference class forecasting to develop more realistic and reliable schedule estimates.

KEYWORDS:

• Schedule delays
• major projects
• reference class forecasting
• infrastructure investment decision making
• optimism

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 Other research has shown that these failure figures are not a fair approximation.

2 The notion of the iron triangle is a basic element of who we perceive success in projects. The iron triangle is a representation of the most basic criteria against which the performance of the project is measured, namely, whether the project is delivered by the due date, within the budget, and to certain agreed scope. The iron triangle has become the standard for routine project success assessment (Pollack, Helm, & Adler, 2018).

3 The estimated schedule was extracted from the financial plan or business case approved after the last change in scope. Consequently, the analyses are not confounded by significant changes in the scope of the projects.