About this Presentation
Prof. Carl Gavin and Tim Stacey ask whether Theory of Constraints may supply the missing system-behavior layer needed to unify project management. They begin with a "memory problem": the profession repeatedly rediscovers ideas while forgetting the system logic that once made them useful. Historical examples trace how time-based bar charts shifted from progress measurement toward planning, how Critical Path Method lost much of its original optimization logic, and how iterative software development existed decades before Agile was framed as a revolution. The point is not history for its own sake; it shows how methods can survive while the logic that made them effective is diluted or forgotten. The presenters then return to the nature of projects. Plans are estimates, while execution exposes resource contention, dependencies, delayed inputs, rework, variability, and nonlinear interactions. Research on IT projects and megaprojects is used to illustrate that failure can become catastrophic rather than simply drift a little beyond the estimate. A simple simulation comparing additive and compounding effects helps frame why interdependency and cascades matter. They also examine whether Critical Chain itself is at risk of being forgotten. Literature data shows the "Critical Chain" name appearing less often while buffer concepts continue to appear, suggesting that the ideas may be diffusing even as the label fades. TOC helps explain and mitigate project failure by reducing WIP, controlling release, synchronizing around the constraint, using aggregated protection to focus management attention, defining done clearly, and checking work-to-go frequently. Gavin and Stacey propose a draft definition of a project as a socio-technical flow system of interdependent activities, decisions, and policies governed by synchronization, constraints, WIP, coupling, and variability that suffers from emergence. Their conclusion is deliberately qualified: TOC is not yet a unifying theory of project management, but it may be the strongest available candidate for the missing system-behavior layer beneath planning and control, flow, and systems of work.
What Will You Learn
To help you get the most value from this session, we’ve highlighted a few key points. These takeaways capture the main ideas and practical insights from the presentation, making it easier for you to review, reflect, and apply what you’ve learned.
Why project management has a "memory problem": tools such as Gantt charts, Critical Path Method, and iterative development can persist while the original system logic behind them is lost or simplified.
Why projects should be understood as interdependent socio-technical flow systems in which variability, coupling, resource contention, and cascades can create nonlinear and sometimes catastrophic outcomes.
How TOC mitigates those dynamics through WIP reduction, controlled release, synchronization around constraints, aggregated protection, clear definitions of done, and frequent checking of work-to-go.
Why TOC may be a strong candidate for the missing system-behavior layer that connects planning and control, flow, and systems of work without requiring the profession to abandon existing project-management paradigms.
Instructor(s)
Carl Gavin
Director of Executive Education and Professor of Project Management
University of Liverpool
Tim Stacey
Tim Stacey is a highly experienced Project Management Professional with extensive experience in the project delivery of military vehicles. His career includes meeting extensive surge requirements for operational requirements (Iraq and Afghanistan) and a leading Project Management role in the Challenger 3 program to deliver the most advanced main battle tank in NATO. Tim has led the use of Critical Chain Project Management / Theory of Constraints within the program.