The Takt Production System – Part 3

The Urinal Test: Why CPM Is a Broken System You’ve Learned to Work Around

Here’s a graphic but accurate analogy: most construction scheduling is like a poorly designed airport urinal. It’s disgusting, there’s always a mess on the floor, and people keep stepping in puddles. The manufacturers keep selling inferior products without caring for the end customer. And when you point out the problem, they say “if people would just aim right, there would be no problem.” Granted. And yet we still have a mess everywhere.

Conversely, there are urinals that work very well, upward-facing bowl shapes that hardly allow any mess. It’s hard to use them incorrectly. You rarely see a mess with this type. Why do they work? Because there’s absolutely no friction in the process of getting it right. It just happens naturally, regardless of how they’re used.

Could someone mess it up if they wanted to? Yes, but they’d have to be trying to get it wrong. Could someone use the first urinals right? Yes, I guess so. So what’s the difference? On a large scale, one is practical and works for the masses with little friction, and the other results in a mess.

If we want to keep stepping in puddles, let’s not change and let’s keep blaming the people. But if we want an easy, clean, and neutral experience, let’s get the proper units and process and help the people to win as a group. That’s the urinal depiction of CPM. And it perfectly summarizes why the system is fundamentally broken.

The Current State: Three-Week Look-Aheads and Crash Landings

Right now, the industry standard is to plan the project with CPM, print look-ahead schedules, and build from a three-week schedule. This will continue to cause the aforementioned problems, and our mission is to share with you information about those issues and their remedy throughout this work.

Our industry is currently benefiting from some parts of the Last Planner System. Typically in the new approach, CPM schedules are created that identify milestones, with the use of the Last Planner System pull planning is done to the milestones, make-ready plans detail out target dates for worker counts and materials and information, and the weekly work plan becomes the production control tool of choice from which the percent plan complete can be tracked as the project team huddles to execute daily work.

This is a step in the right direction, but it won’t be fully supported until CPM stops leading as the unruly master with its unrealistic end dates and poor preparation. Is Last Planner perfect? No. Are there some concepts that have to be clarified and modified? Yes, and we will show that in this book. As for Scrum, we couldn’t be more excited about the possibilities of using this system, and it excites us to have a system that will prepare for Scrum sprints by controlling the supply chains ahead of it. Ultimately, Takt planning is a system that prepares for short-interval production control, whether you use standard Takt control or Last Planner or Scrum.

Flow Must Reign Supreme

So why the need for this book? In Lord of the Rings, it was not originally known that the one ring held power over them all. Similarly, in construction, we have not come to the conclusion yet as a whole that flow rules all other efforts and that it must reign supreme.

Our story is one of teamwork, transparency, and success that begins with respect, creating stability, and continuously improving. Because construction relies so heavily on supply chains of materials, worker counts, and information, the rhythm of a project and the overall throughput will always need to be the first key considerations—even if we employ agile techniques on a short-interval basis.

In the Book of Five Rings by Miyamoto Musashi, the author describes short sword and long sword martial arts. The long swords are used in open warrior-to-warrior combat. The short sword is used in close proximity situations when dueling. A martial artist needs both. Musashi explains that a great martial artist will hold both swords in combat and focus his or her eyes on a fixed position toward the enemy so as to see the peripheral and not get distracted.

In construction, we cannot get distracted by one type of scheduling, one critical path, or one method. We need to keep our eyes forward and fixed on the enemy—waste and variation. If we do this, we will use systems together like Takt, Last Planner, and Scrum. We must fight with a short sword (short-interval planning methods) and long swords (master schedules like Takt planning) and keep our eyes fixed on flow and the overall throughput of the system and not get distracted by a single critical path.

Takt planning has not yet taken hold in the United States like it should, and it needs to be empowered as the main scheduling tool to either replace the critical path method or at a minimum to hold it accountable and govern it. One of the main reasons the construction industry still typically produces projects behind schedule with a crash landing at the end and with poor quality is because we incentivize this with the variation, lack of transparency, and chaos that comes from true CPM scheduling. It is time for this to stop. And Takt is the solution.

The Critical Path Myth: Buffers Are Required, Not Optional

Let’s talk about the details. We all know the concept of a critical path, right? Or do we? Here’s one definition: in project management, the critical path is the longest sequence of tasks that must be completed to successfully conclude a project from start to finish. The tasks on the critical path are known as critical activities because if they’re delayed, the whole project will be delayed.

This is the most common definition. And again, let us be clear: you should never have just a critical path without buffers. There are some in construction that have not allowed buffers in contract language and schedules, which is wrong.

Anyone who has managed risk in construction would attest that traditional CPM has always been missing the statistical probability of completing on time. This is why risk by duration certainty and risk event charting is analyzed to show us the likelihood of success. This gives the rationale for buffer and buffer management to be in any schedule management system. So the critical construction activities by themselves are not a responsible execution method.

This is why you might have heard of CCPM, critical chain project management—which takes buffer management into account. And if we should not have a critical path, why would we want a forward and backward pass to find it? The answer is we wouldn’t.

True CPM vs. Builder CPM: You’re Not Defending What You Think You’re Defending

Most construction builders use flow principles that awkwardly fit into CPM. For instance, a critical path for most builders means the longest string of activities in construction that also includes an activity buffer for the overall schedule. So we do not plan on 100% efficiency within the projection of the activities. But that is not the true definition of a critical path. So let’s differentiate between true CPM and builder CPM, because we want to convince you that true CPM as a standalone system is not serving you well and convince the world that builder CPM is better done in Takt.

As a very wise lean practitioner once said, you can learn to walk with a broken leg, but it would be better to just fix the leg. When people tell us they can do what we do in Takt with CPM, we always ask why. Why spend 12 times the amount of time developing it, overburden the team to manage it, and hide the information within it just to save the 12 hours it would take to learn Takt? The answer is that you wouldn’t and you shouldn’t.

One more thought here: when people push back about the use of CPM, they always say it’s not the process, but people are using it wrong. We blame processes, not people in lean thinking. If CPM is not implementable across the industry in its basic form without people using it wrong, then it is fundamentally broken. Even in the Bible, Paul in the book of Romans spoke about things not being unclean or evil in and of themselves. But when they show forth a bad example and others are hurt by it, then it is unclean and evil. You may be able to make CPM work the way you want, but your example in using it is hurting the 74% of construction projects that fail.

What Builder CPM Actually Looks Like

Here’s what true builders actually do with CPM—and why it proves the system is broken:

Critical Path: True builders add contingencies at the end of their schedules and call that the critical path. Why? Because they know it doesn’t work to plan on 100% efficiency, so they plan in a buffer at the end. That’s good, but now it’s technically not a critical path.

Float: True builders focus more on crew ties for trade flow than they do float and early and late starts and finishes. Many true builders will tell us they create flow in the schedule with logic ties. But then again, you do not have a critical path. Instead, you have a flow analysis—and one that is not easily seen as a point of fact.

Forward and Backward Pass: True builders will level out the work instead of allowing the algorithm to slam everything to the left toward the data date with a float calculation. Most of the time, builders do not even show project float in the schedule. So why does it matter? The answer is it doesn’t.

So you see, when people get offended at us and defend CPM, they’re not defending true CPM. They’re defending builder principles they have fit into builder CPM, incorporating their wisdom into a broken system. Now you can keep using that broken leg, or you can get it fixed and enjoy your life. Ultimately, we feel you would be happier and have more family time if your priority was on living a remarkable life instead of holding on to the significance of being a CPM expert and user.

Float Calculations Are Useless and Dangerous

You should never schedule a project with a critical path that has no buffers. And what about the float calculation? That’s useless too. Showing the allowable float breeds a mindset that activities can and should be moved at random. That increases work in process, extends throughput times, and creates restarts. All of that decreases flow efficiency and resource efficiency.

Once we randomly start an activity with free float or total project float outside of a flow, we’ve created variation in the entire system and the teams executing the work. Therefore, we do not need a critical path, a forward and backward pass, early and late start and finish times, and a complex network diagram that does not visually show what we’re doing. So why do so many competent people still use it? It’s because they use what we call builder CPM, not true CPM.

How to Transition: Takt First, CPM Only When Required

Here’s a question: how can we transition an industry from CPM to Takt? Well, education to start. Eventually, owners and government agencies will need to remove it from contracts. But at a minimum, Takt should govern and control CPM if it’s still used.

If you have to do this, and you’d be surprised at the number of times you actually don’t, it’s our recommendation to plan your project in Takt, create a CPM schedule to appease the owner just in time and only at contract minimums, or even better, use the Takt plan to govern the project and use CPM for the as-built to show the owner status.

We believe you could implement the last option on almost any project. And why keep both systems, you ask? Again, we don’t know. You should switch to Takt or at least negotiate the schedule reporting terms of the project away from CPM language. There are plenty of standard contracts that already do this and still give reports to the owner while also mitigating risk.

We hope this work convinces you that there’s a better way, that you deserve better, that people matter enough to create flow, and that learning a new system is easier than you think. If the friction is that your owner wants an application with metrics, most all desired metrics can be calculated in Excel as one of the best options for starting to use Takt. You can also consider using Tacting or Timotei with some facilitation.

If you’re ready for something new, though most importantly something that works, keep reading. We’ve written this book in a manner to match the fables used in Patrick Lencioni’s books. From here you’ll be introduced to the concept of flow and Takt planning in our story, after which we will detail how to implement Takt successfully so you can begin the use of flow and Takt planning on your projects. If your project needs superintendent coaching, project support, or leadership development, Elevate Construction can help your field teams stabilize, schedule, and flow.

FAQ

Q: What’s the difference between true CPM and builder CPM?

True CPM uses a forward and backward pass to find the critical path with no buffers, plans on 100% efficiency, calculates float, and slams everything to the left toward the data date. Builder CPM is what competent builders actually do: they add contingencies at the end (so it’s no longer a true critical path), focus on crew ties for trade flow instead of float, level out work instead of letting the algorithm slam it left, and often don’t even show project float. When people defend CPM, they’re defending builder principles they’ve awkwardly fit into a broken system. You can keep using that broken leg, or you can fix it and use Takt.

Q: Why is showing float in a schedule actually harmful?

Showing allowable float breeds a mindset that activities can and should be moved at random. That increases work in process, extends throughput times, and creates restarts. All of that decreases flow efficiency and resource efficiency. Once you randomly start an activity with free float or total project float outside of a flow, you’ve created variation in the entire system and the teams executing the work. Float calculations give false permission to disrupt flow, which is the opposite of what construction needs.

Q: How can I transition to Takt if my owner requires CPM in the contract?

Plan your project in Takt first. Then create a CPM schedule to appease the owner just in time and only at contract minimums. Or even better, use the Takt plan to govern the project and use CPM for the as-built to show the owner status. You’d be surprised how many times you can negotiate the schedule reporting terms away from CPM language, there are plenty of standard contracts that already do this while still giving reports to the owner and mitigating risk. At a minimum, Takt should govern and control CPM if it’s still used.

Q: Why do you say CPM is fundamentally broken if people keep using it wrong?

We blame processes, not people in lean thinking. If CPM is not implementable across the industry in its basic form without people using it wrong, then it is fundamentally broken. It’s like the poorly designed airport urinal—you can blame people for not aiming right, but the real problem is the design creates friction in using it correctly. When 74% of construction projects fail, and competent builders have to modify CPM with buffers, crew ties, and leveling just to make it work that proves the system itself is the problem.

Q: What’s the urinal analogy really saying about construction scheduling?

On a large scale, one urinal design is practical and works for the masses with little friction, and the other results in a mess. CPM is the poorly designed urinal, it creates friction in getting it right, hides the mess in complexity, and requires experts to make it work. Takt is the well-designed urinal, it’s hard to use incorrectly, creates flow naturally, and works for everyone from laborers to executives. If you want to keep stepping in puddles, keep using CPM and blaming people. If you want an easy, clean, neutral experience, use Takt and help people win as a group.

On we go.