Critical Chain: why isn’t it much more common?

I first read Goldratt’s book “Critical Chain” in the late 1990’s. I had just completed a successful project and remember thinking it would have been great to try it on that project. It seemed to be a close fit with the ‘project alliance’ collaborative project contracting approach we had used on that project.  

Eventually, 20 years later, I wrote a book about this synergy, and it was the topic of an APM Real World Project Management webinar in early 2018. 

After reading Goldratt’s book, my career took a different path and that was to be the last large project I managed as a hands-on project manager (PM). 10 years later, when working at a UK construction company, I noticed that critical chain wasn’t being used — in fact, hardly anyone had heard about it. I assumed it was one of those neat ideas that didn’t go anywhere. 

How wrong I was. 

Rediscovering critical chain

In 2010 I attended a training event in Israel on the Theory of Constraints (TOC) — the broader approach to management from which critical chain was developed. Eli Goldratt, the charismatic genius behind TOC (and critical chain), joined the group one afternoon for a Q&A session, so I asked him what happened to critical chain.  

He said it was very much alive and well. 

Along with examples from different companies and sectors, he told us how it was a key element in the Japanese Government’s programme to improve public infrastructure. The following year I was fortunate to spend a morning with a senior official at the MLIT ministry in Tokyo and got to hear firsthand about their construction project improvement initiative based on critical chain and TOC. 

This started me on a continuing journey to understand how this relatively new approach to project scheduling and control was being used — apparently successfully — in many project domains.  

APM publishes the Senior Manager’s and Project Manager’s Guide to Critical Chain 

The latest step in this journey was a small role I played in supporting René Nibbelke of BAE Systems plc in writing the APM Senior Manager’s and Project Manager’s Guide to Critical Chain, published in October 2024. 

The Guide outlines the key elements of critical chain and compares it with other scheduling and control approaches. It also discusses managing organisational change when piloting and adopting critical chain. 

The Guide is based on the recent experiences at APM Corporate Member BAE Systems plc. They are nearly four years into a global initiative on critical chain, which René discussed in a recent APM News article. The Guide is published by the APM in collaboration with the TOCICO — the international body for TOC. 

Who else is using it and on what kinds of projects? 

In between meeting Eli Goldratt in 2010 and the recent publication of the APM Guide, I have spoken with over a hundred project professionals from many parts of the world about their experience using critical chain. 

These come from a wide range of different project domains, from very large single projects to portfolios of smaller projects.  

At one extreme is a landscape gardening contractor in California struggling to cope with a portfolio of 25 customer projects — before using critical chain. At the other is a multi-billion project to design and launch a new passenger aircraft. 

In my domain of capital projects and construction, I have spoken with people who have used it building new factories at a rapidly growing company, modifying city infrastructure ahead of the Euro 2012 football tournament, building new roads in Brazil and a hospital in Chicago. 

Everyone I spoke to told a similar story. They got “textbook” improvements in performance. The same teams, with the same supervisors, tackling the same kinds of problems, started performing better with much less stress and firefighting. Simply by changing how they scheduled their projects and portfolios and how they managed execution and control. 

And those “textbook” improvements are not trivial. Several of these cases said they more than doubled the number of projects they were completing, whilst at the same time moving to 90%+ predictability. The APM Guide cites one study showing an average of 39% duration reduction whilst making a 70% improvement in schedule adherence. 

At a 2016 conference in the USA, I heard Seita Kanai the chairman of Mazda Motors say using critical chain was instrumental in saving the company (they used it to double the productivity of their R&D projects). One of the guest lecturers on our MSc course, a VP at Embraer, shared their story of using it to develop and launch a new passenger jet in two-thirds of the time it took Boeing and Airbus. 

Understanding critical chain 

One of the difficulties I come across in discussing critical chain with project managers is that it doesn’t fit neatly into any single project management discipline. 

Is critical chain a scheduling method, a project control method, or an approach to leadership and governance? It’s all of these. 

The current APM Body of Knowledge (2019) covers critical chain as a scheduling method, but scheduling is not where critical chain adds most value. Over time I have come to realise that the benefits from using critical chain come more from execution/control practices than the schedule itself.  

In fact, you can use some critical chain practices without the specific scheduling technique and associated progress measures. The APM Senior Manager’s and Project Manager’s Guide to Critical Chain describes the critical chain approach using “10 Rules of Flow”, several of which can add value to many projects, irrespective of how they are scheduled and controlled.  

Implementing only rules 1, 2 and 3 with no scheduling software or formal progress reports, Balthazar Martinez (owner of the landscaper mentioned above), went from a 70+ hour workweek to under 40. Within a year he increased the number of projects done by 50%, and halved the average project duration, with the same employees working fewer hours. Ironically the client who advised him to change only the management practices was the owner of a critical chain software company. 

When one of our MSc students introduced critical chain at his employer GSK, he used all the rules of flow, including critical chain scheduling and progress measuring. I loved the way a senior project stakeholder described why he preferred the critical chain approach. 

Before critical chain, he felt frustrated because most of the reporting was retrospective. It gave good explanations of what the problems were … Too late for him to do anything other than react. This led to him asking more detailed questions and being seen as interfering or micromanaging. 

Now with critical chain he felt much more confident that project teams would proactively involve him as soon as they noticed a potential issue. “Now the fever chart flags potential issues in advance, and I can help overcome obstacles and prevent problems escalating.” 

So why not? 

If you’re not using critical chain to schedule and manage your project execution, why not get yourself a copy of the new Senior Manager’s and Project Manager’s Guide to Critical Chain, and watch the presentations the TOCICO have shared? 

Then why not give it a try? 

 

You may also be interested in:

• Critical chain method
• What is scheduling in project management?
• Interview with René Nibbelke