Certified Free Flow Master

Solutions for the "Certified Free Flow Master"

February 1, 2022

OK, it's clear I'm not a fan of all these certifications - but it's fun to build one! So I generated one, the "CFFM - Certified Free Flow Master!"

If you can answer five questions, you know everything needed to really master flow. So let's start:

#1 What is the definition of Lead-Time and Touch-Time?

The lead-time is the duration an item needs to be processed. The duration starts at the moment when the item is released into the workstream and ends at the moment when it comes out of the workstream. It all depends on how you look at your system. Before a workstream, there is often a backlog; therefore, from the perspective of the workstream, the lead-time is from the start to the end of the work, while from the perspective of the customer, it includes the waiting time in the backlog ;-) - quite a difference.

The touch-time is much easier. It is the sum of all durations when someone actively works on the item, fully concentrated and with as many resources as possible. For example, the touch-time involved in producing a screw is somehow milliseconds! Just the cutting and the forging. All the waiting and transport times are left aside.

#2 What does Little's Law say?

In the original version, it goes like this: *L=lambdaW, with L as the number of items in the system, lambda as the arrival rate, and W as the waiting time. It is only applicable when the arrival rate and the finishing rate are equal - obviously, otherwise the system will dry out or explode. Therefore, process managers often use Little's Law like this: Lead-Time = Work-in-Process/Throughput**. The conclusion of this law is that the lower the WIP, the shorter the lead-time (or time-to-market)!

#3 What is the difference between Projects and Processes?

Oh, there are many differences. But only one of them is relevant for process managers, and it is often forgotten. The main structural difference is that in a process, the touch-time is much lower than the lead-time! We talk about a process if the touch-time is below 20% of the lead-time. What? Yes, that is important - if you have many items to work on in your system and the touch-time is so small, then it's easy to manage the system just by changing the order of the items in a queue (backlog). If the touch-time gets bigger, then you have to track even the progress on the critical chain of workstations - if the touch-time gets higher than 30% of the lead-time, you are already in the domain of projects.

That is important for understanding why backlog-oriented flow controls often have longer overall lead-times than project organizations. But doing everything in projects is also not a good idea because projects are more complex and therefore more expensive - but they can deal with higher touch-times. There is no silver bullet!

#4 What does Goldratt's Law say?

Very few know about this (see Eliyahu Goldratt). It is more or less common sense - but it is always violated in working life. It goes like this: Throughput = average Capacity in the Constraint / average Effort in the Constraint!

The interesting part is the "Constraint"; therefore, it is often called the "Theory of Constraints" or #TOC. The main assumption is that "All open systems that produce something have ONE constraint that defines the maximum throughput!" This is easy to explain - without a constraint, the system will consume all resources in an infinitely short time and explode - that is, die. With two constraints, the system will begin to oscillate - no longer as effective. With three or more active constraints, you'll see chaotic behavior - even less effective - and if another system emerges in the market with fewer constraints, it will win. So, in the end, most systems will show exactly ONE constraint - it's simply the most effective configuration that does not explode ;-)

The conclusion from this is dramatic. Forget about all the rest - just focus on the constraint! To get the best output, don't overload the constraint (typically, load it to just 80%). But if the constraint is loaded to just 80%, then the rest of the resources should be loaded less (often ~60%) - cool! Resources are waiting for work - and at that moment, you get maximum Throughput!

Side note - if you increase the throughput in the constraint, then the time to market (lead-time) will drop again; see #2, Little's Law.

#5 What is this thing called "Virtual Drum"?

Now it gets creepy! One conclusion from the Theory of Constraints is also: "The more complex a system is, the stronger the constraint has to be to keep the system alive!" This means the more complex a system is, the more abstract a constraint must be!

So production is "simple": often one value stream - sometimes linear, sometimes with feeding chains. It is not very complex, so there is a real constraint! This is mostly a workstation with the lowest capacity or the longest takt time.

In knowledge work (or projects), it's not so simple anymore - it's much more complex. You do not know the touch-times (because you have never done it before), you don't know exactly who you need, and often people are sick at the moment you need them. So you can't estimate, and you don't know whether you have the resources you need - very complex! In this case, you don't find a real constraint anymore - it's more of a critical phase in the project when you need to do the concept or bring the project to life - then you need the best people or decisions. Because you don't know whom you need, we call this phase a "virtual drum." And we call it a "drum" because it's very useful for determining the start and end dates. If something goes out of the drum, something new can go in - it's a pipeline driver - like the drum on a boat!

P.S.: There are even more complex systems. Then the drum is in the market - very complex - and it's very easy to set up the control system for this. But that is just for the ACFFM, "Advanced Certified Fun Flow Masters" ;-)

P.P.S.: If you want to apply this to your company, here are some hints:

1. If you want to know how much potential you have, use our new free Constraint Analytics Center, a.k.a. 99/1 ... you'll find your constraint and get your Multitasking Score, the Potential for Flow, and, if you want, even a Business Case - all packed in a PDF that you can show to your managers.
2. If you want to start immediately and need some Excel tools and descriptions for advanced agile stuff, Everything you need for agile or classic projects - also for free!
3. OK, and if you need help doing all this, the DolphinUniverse Community offers some lightweight support - join the community for free