Manufacturing Breakthrough Blog
Thursday July 9, 2015
At the end of my last post, I asked you to think about the following scenario. I explained that we want to improve the quality of our product that we manufacture. I also explained that our current defect rate was at nine percent and that we wanted to get it below five percent. My question to you was: which type of logic (i.e. necessity or sufficiency) would you use to develop the plan?
If you answered by saying both types of logic, you would be partially right. However, you will see in future posts, using sufficiency-based logic involves putting together a series of if/then statements to determine the core problem that is negatively impacting your organization and then developing a solution to the problem. That is a good pathway to improvement.
In my opinion, sufficiency-based logic is the better pathway because you will identify all of the “things” you will need to develop your actual improvement plan. You will use the syntax, “in order to have A we must have B” and, as you will see, there will be multiple “Bs.” This will become more apparent when we discuss the Goal Tree in a future post.
The Thinking Process Diagrams
In my last post, I identified six logic diagrams that make up the Thinking Processes. The six, along with the type of logic each one uses are:
- Current Reality Tree—Sufficiency Logic
- Evaporating Cloud (EC)—Necessity Logic
- Future Reality Tree (FRT)—Sufficiency Logic
- Prerequisite Tree (PRT)—Necessity Logic
- Transition Tree—Sufficiency Logic
- Goal Tree—Necessity Logic
In today’s post we will discuss the intent of these diagrams, or what we hope to achieve by using them, and the “rules” for using them. These logic diagrams are intended to answer the three critical questions I have discussed in previous posts:
- What to change?
- What to change to?
- How to cause the change to happen?
You may be wondering which of these logic diagrams answers which question(s). The following table summarizes when to use each one:
“If A then B”
“In order to have A we must have B”
What to change?
Current Reality Tree
What to change to?
Future Reality Tree
How to cause the change?
The Rules of Logic
For sufficiency logic, there are eight “rules” that must be applied to each of the three using sufficiency-based logic. These rules are referred to as the Categories of Legitimate Reservation (CLR) and are intended to validate (or invalidate) or test the logic of the cause and effect connections that we develop. These eight rules and a brief explanation of each one are as follows:
- Clarity reservation—The complete understanding of a word, idea or causal connection. In other words, requesting additional explanation because you don’t fully understand the cause and effect relationship or the individual entities as stated.
- Entity existence reservation—The verifiability of the existence of a stated fact or statement. In other words, you are questioning the actual existence of the cause or effect entity.
- Causality existence reservation—The direct connection between a proposed cause and the effect. Questioning the existence of the causal link between the cause and the effect.
- Cause sufficiency reservation—The complete and unequivocal accountability for all stated causes that supposedly produce the effect. Using another effect to show that the hypothesized cause does not result in the initial stated effect.
- Additional cause reservation – The existence of a completely separate and independent cause of a particular effect.Explaining that an additional non-trivial cause must exist to explain the observed effect.In other words, neither cause by itself can account for the effect.
- Cause/effect reversal reservation—The misalignment of cause and effect. That is, the effect is actually the cause.
- Predicted effect existence reservation—An additional expected and verifiable effect coming from a specific cause. Using another effect to show that the hypothesized cause does not result in the initial effect.
- Tautology—Circular logic where the existence of an effect is offered as rationale for a stated cause. Being redundant in stating the cause and effect relationship.
The Categories of Legitimate Reservation are essentially proof-reading tools to use when constructing the logical cause and effect trees. Remember these CLRs are only used on the trees using sufficiency-based logic.
Cause & Effect Relationships
Undesirable Effects and Core Problems
Over the years, one thing that I typically see when I go into a manufacturing company is firefighting. And when I question the leadership on whether this is a new problem or not, they typically tell me that they always seem to be solving the same problem over and over again. This is symptomatic of a company that is treating the symptoms of a problem rather than identifying the underlying core issues or drivers of the problem. These same companies tend to repair or improve the symptoms of the problem they haven’t identified.
What these companies desperately need is a systematic way to go below the symptoms to discover the actual core problem. This is exactly the purpose of the Current Reality Tree (CRT). So the starting point for this logic tree is to list the symptoms we see in our current reality. We’re not looking for petty gripes or things that we observed years ago, we’re looking for symptoms that we’re seeing today. The fact of the matter is, most of the symptoms we are seeing are coming directly from a single core problem or a core conflict. If we identify and remove the core problem (or core conflict), we may very well be able to remove most of the symptoms as well. In TOC terminology, these negative symptoms we are seeing are referred to as undesirable effects (UDEs) and they are linked through cause and effect.
The Current Reality Tree
A current reality tree is a graphical representation of an underlying core problem and the symptoms (UDEs) that arise from it. It maps out the cause and effect sequence from the core problem to the UDEs. The great thing about the CRT is that if you are able to successfully eliminate the core problem, then most if not all of the UDEs will disappear. Operationally we work backwards from the apparent undesirable effects or symptoms to uncover the underlying core cause.
In the CRT below there are eight negative symptoms, or UDEs, with a single core problem identified. Each of the UDEs are linked through cause and effect and are read as, If…..””the core problem”…., then UDEs 4, 5, 6 and 7 will exist. If UDEs 5 and 7 exist, then UDE 8 will be present. The ellipse is the symbol for the logical “and” statement which, in this case, means that both UDEs 5 and 7 must exist in order for UDE 8 to be present. If UDE 8 is present, then UDE 3 will also be present. Likewise, if UDE 6 is present then UDE 1 will occur, and if UDE 4 is present then UDE 2 will be observed. So as you can see, all of the UDEs are linked to a single core problem and if it is removed, then all of the UDEs will go away.
A Question to Ponder
In my next post we’ll look at a real example of a Current Reality Tree and discuss how to construct it in more detail. As always, if you have any questions or comments about any of my posts, leave a message and I will respond.
Until next time.