Novel and effective project management with the Critical Chain approach

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Article published in October 2018 in the French magazine Informations Entreprise


Published in Informations Entreprise n°170, October, November and December 2018. The English translation of the text of the article is below the image.

Informations Entreprise

Read the article (Fr)

Transforming companies significantly, rapidly, and in a sustainable manner is what Marris Consulting does. It helps its clients improve their performance, particularly in project management, thanks to an innovative approach: the Critical Chain.

The Critical Chain approach, that appeared in the late 1990s, is used by hundreds of companies around the world: Boeing, Procter & Gamble, Eli Lilly, NASA, Medtronic, US Air Force, Mazda ... In France the best known practitioners are: Safran, Yves Rocher, Thales, Teledyne e2v, Embraer & Euro Cryospace (Ariane rockets). The results obtained by traditional methods of project management, such as the Critical Path method, are disappointing. Too often, there are significant delays and budget overruns. Philip Marris, founder and CEO of Marris Consulting, recommends an innovative and alternative method: Critical Chain Project Management (CCPM).

This approach is part of the Theory of Constraints (TOC) developed by Eliyahu M. Goldratt (with whom Philip Marris worked) in the bestseller The Goal that has sold over 7 million copies in 30 languages. In twenty years, the Critical Chain method has proved itself in the world of projects: reduction of the duration of projects by 39% on average, increase of more than 50% of the number of projects completed with the same resources and greatly improved proportion of projects finished on time. In addition, the Critical Chain creates a much better working environment: less stress, more trust and transparency between the different actors, less chaos and bad multitasking and better visibility on current and future activity. As a result, during an implementation there is little resistance to change because it is a win-win solution for all, from operational resources to the executive committees.


Project planning according to the Critical Chain method

Critical Chain can be applied to an isolated project but also to project portfolios. The approach is based on 3 strong principles: to break the unhealthy policy of commitments on the dates of completion of each task, to plan the projects by taking into account the capacity of the resources and to focus the management on what is critical: the "Critical Chain" that determines the performance of the project.

The first step is to identify the tasks needed to complete the project and determine their duration. Traditionally, to respect the overall timeframe of a project, it is emphasized that each task respects the dates defined by the initial planning. As a result, to compensate the uncertainties and honour the commitments, each manager increases the duration of each of his tasks with a safety margin. However, despite this, the projects are late because these local safety margins are wasted by different behaviours: student syndrome, Parkinson's law, multitasking and calendar syndrome. Where conventional project management methods use durations increased by a margin of safety, the Critical Chain uses "focused durations" corresponding to the actual average work time on the task under perfect working conditions; the "focused time" to perform the task, without interruptions, without risks or complications and with a probability of 50% to exceed this duration. In doing so, it is generally observed that the expected durations of the tasks are reduced by about half on average. Local safety margins are removed and shared in a global protection, at the end of the project, called "project buffer". This agreggation enables the project buffer to be smaller than the sum of the margins of the tasks. This protection protects the entire project from problems that may occur on any task during the execution of the project. For this reason, the Critical Chain training sessions hosted by Marris Consulting have the provocative title: "Dare to finish all your projects on time!" The next step is the levelling of resources, in which task dates are adjusted based on resource availability. When the levelling is not done, the same resource may be assigned to multiple activities at the same time, which is unrealizable... and common in multi-project environments managed in a traditional way.

Then we identify the longest sequence of tasks to determine the duration of the project, but unlike a classic Critical Path that takes into account only the logical dependencies (the predecessor-successor link between the tasks). The Critical Chain takes into account the resource dependencies, and this sequence of tasks is the constraint of the project. It is this sequence of tasks that really determines the duration of the project. Sinc the focused durations used in the planning don’t take into account the uncertaintities and probable execution problems, a project buffer is inserted at the end of the project. The planned project end date is therefore the end date of the project buffer. Finally, to prevent non-critical activities from delaying the project, the Critical Chain is protected from the potential drift of non-critical activities by so-called feeding buffers.


Project execution according to the Critical Chain method

The Critical Chain approach contains several innovations to drive the execution of projects. First of all, the tasks of the Critical Chain must follow each other as quickly as possible. To do this, Marris Consulting recommends using the principle of relay baton thanks to a mascot - a remarkable object like a big teddy bear - that follows the Critical Chain from office to office. Another solution has been used by Safran in particular: people who must work on the Critical Chain isolate themselves in a dedicated office without the possibility of incoming calls. Secondly, project management is based on a simple visual indicator called the Fever Chart. The Fever Chart is a factual indicator of the status of a project allowing anticipation rather than working in a firefighting mode. It is built by measuring the progress of the project (percentage of achievement of the Critical Chain) and the consumption of the project buffer. In the example of Figure 5 the project finishes early. To finish projects on time in an uncertain world we must aim to finish them in advance - when we take a plane, we plan to waste time waiting at the gate. The Critical Chain approach is also very often used to manage project portfolios (the development of new products for example). This is facilitated firstly by the fact that each project is well planned and that the execution rules are sound. Secondly, the Portfolio Fever Chart makes it possible to manage the priorities of the actors between the projects in an objective and dynamic way at any time. This system can easily integrate projects of different sizes because the two axes are calculated in percentages. "Note, adds Philip Marris, that we can therefore easily include in the same portfolio projects of one year and one month side by side." Rather than frequent meetings to decide which project is more important, the one which is very important and late, or the one which is less important but very late, we can objectively and transparently identify which of several tasks is objectively a priority. Finally, in the case of project portfolios, we avoid clogging up the organization by launching more projects than the capacity of the resource that is the capacity constraint of the system. In this way we avoid creating queues and causing excessive multitasking. The launches of new projects are decided accordingly. This aspect of CCPM is called "sequencing" or "pipelining".



Philip Marris recommends not using Critical Chain alone. The Critical Chain is a way of managing projects but it does not deal with the quality of the project itself. We must combine the approach with "Agile" approaches especially in some software development environments and/or with Lean Engineering or Design for Six Sigma in the development of new products. Not to mention the basics of project management (PMI, ITIL ...) such as risk management, the use of which becomes easier because of the improved working environment. The fires are extinguished, firefighters can become builders again. "I do not know any management approach that is as appealing as Critical Chain," says Philip Marris, "it's easy to understand because it's only common sense and everyone wins. The projects go much faster, we do a lot more with the same resources and we can finish them almost all on time and all this in a healthy and serene work environment based on transparency and trust. "


Key figures of Marris Consulting

2005: Year of creation

> 200: number of company transformations carried out by employees

> 40%: the part of the activity carried out outside France (England, Mexico, Romania, South Africa, Czech Republic, China, Switzerland ...)

30: the number of conferences and inter-company training sessions per year

20%: annual growth

> 200: videos on the Marris Consulting YouTube channel

Its motto: Factories, People & Results


Some clients of Marris Consulting

ArcelorMittal, Arkema, Ariane Group, Autoliv, Bayer, Bosch, Bulgari, Embraer, GSK, Lilly, Louis Vuitton, Procter & Gamble, McDonald’s, Nexter, Rolex, Safran, Siemens, SKF, Thales, Veolia, Yves Rocher…


Express Biography of Philip Marris

Philip Marris is English and based in Paris. He discovered early in the 1980s both "Lean" and the Theory of Constraints. Since then he has implemented them together in varied environments; the design and production of cars, trains, planes, handbags, hamburgers, etc.


About Marris Consulting

Marris Consulting is an industry consulting and training company specialized in the Theory of Constraints (ToC) and Critical Chain Project Management. We focus on improving the performance of manufacturing and process industries by using Constraints Management combined with Lean and Six Sigma. To boost project performance, we also use Critical Chain Project Management (CCPM), which we sometimes combine with Lean Engineering. Our 2-day performance audits, our performance consulting services and our project management, Lean, ToC & CCPM training by our industry consultants offer a wide range of solutions to help our clients around the world reach the highest possible levels of performance.

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