Decision Inertia

Project Business Management

SERIES ARTICLE

By Oliver F. Lehmann

Munich, Germany

“Wrong decisions made early can be recovered from. Right decisions made late cannot correct them.”
– From: 100 Rules for NASA Project Managers^[1]

Summary

Projects rarely die from one bad call. They die because people cling to yesterday’s decisions long after reality has moved on. In cross-corporate Project Business — where customers, contractors, and partners juggle risks and incentives — early choices harden fast and become untouchable. This article exposes that silent killer: decision inertia. Three case stories — Titanic, Fukushima, and a modern logistics software fiasco — reveal the same pattern: assumptions turned into dogma, warnings brushed aside, and pride defending decisions long after their justification evaporated. The message is blunt: update your decisions, or they will update you. The article ends with concrete steps leaders can use to break decision inertia before it breaks their project.

Introduction

Projects sometimes fail because people make bad decisions. They may also fail because people make good or necessary decisions and then refuse to revisit them when circumstances change. In cross-corporate Project Business – where customers, contractors, regulators, and suppliers interact under commercial pressure – early choices tend to harden quickly. Once locked in, they outlive their logic.^[2]

This mechanism has a name: decision inertia.^[3]

Decision inertia is not indecision. It is the opposite. It is the stubborn continuation of a once-reasonable path long after the underlying assumptions have collapsed. It shows up in maritime disasters, industrial failures, and modern customer projects just as reliably as in history’s most tragic engineering stories. And it thrives particularly well in project networks, where responsibilities are distributed, information is uneven, and everyone quietly hopes that someone else will raise the alarm – and absorb the costs of doing so.

The following three case stories – Titanic, Fukushima, and a modern software project – demonstrate how decision inertia forms, why it persists, and what it costs. Each example shows different industries, technologies, and eras. Yet the pattern is always the same:

early assumptions treated as permanent truth,
warning signs discounted or ignored,
decisions defended long after their justification has evaporated,
and a cross-corporate environment that makes adaptation harder than sticking to the plan.

Projects succeed when decisions remain alive, revisited, questioned, and adjusted. They fail when decisions become fossils.

These stories show why vigilance, humility, and structured re-evaluation are not optional – they are essential countermeasures against the most dangerous force in Project Business: a decision that should have been updated but wasn’t.

More…

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Editor’s note: This series of articles is by Oliver Lehmann, author of the book “Project Business Management” (ISBN 9781138197503), published by Auerbach / Taylor & Francis in 2018. See author profile below.

How to cite this article: Lehmann, O.F. (2025). Decision Inertia, PM World Journal, Vol. XIV, Issue XII (December). Available online at https://pmworldlibrary.net/wp-content/uploads/2025/12/PMWJ-Dec2025-Lehmann-Decision-Inertia-in-Project-Business.pdf

About the Author

Oliver F. Lehmann

Munich, Germany

Oliver F. Lehmann, MSc, ACE, PMP, is a project management educator, author, consultant, and speaker. In addition, he is the owner of the website Project Business Foundation, a non-profit initiative for professionals and organizations involved in cross-corporate project business.

He studied Linguistics, Literature, and History at the University of Stuttgart and Project Management at the University of Liverpool, UK, where he holds a Master of Science Degree (with Merit). Oliver has trained thousands of project managers in Europe, the USA, and Asia in methodological project management, focusing on certification preparation. In addition, he is a visiting lecturer at the Technical University of Munich.

He has been a member and volunteer at PMI, the Project Management Institute, since 1998 and served as the President of the PMI Southern Germany Chapter from 2013 to 2018. Between 2004 and 2006, he contributed to PMI’s PM Network magazine, for which he provided a monthly editorial on page 1 called “Launch,” analyzing troubled projects around the world.

Oliver believes in three driving forces for personal improvement in project management: formal learning, experience, and observations. He resides in Munich, Bavaria, Germany, and can be contacted at oliver@oliverlehmann.com.

Oliver Lehmann is the author of the books:

“Situational Project Management: The Dynamics of Success and Failure” (ISBN 9781498722612), published by Auerbach / Taylor & Francis in 2016
“Project Business Management” (ISBN 9781138197503), published by Auerbach / Taylor & Francis in 2018.

His previous articles and papers for PM World Journal can be found here: