When confronted with a problem, it is necessary to identify what kind of problem it is as, overall, there are two types:
Type 1 : return to the initial state (reboot/restart)
The desired system performance has already been attained by this system but is no longer being attained today, or is only attained from time to time. In this situation the type of problem is the "Return to the initial state" problem, where the parameters that are preventing the system from operating at its ideal state need to be identified.
Type 2 : Performance improvement
The system's desired performance was never reached. In this situation the type of problem is the "System performance improvement" problem. This type of problem is generally more complex than type 1 where the DMAIC method would be used.
In this section we will specifically focus on the "Return to the initial state" problem type and will describe which tools can help resolve the problem in the most efficient way possible.
Various types of problems (Vinck's iceberg)
Solving a problem requires making people and processes communicate, but we must know when.
D.Vinck summarized our knowledge using an iceberg to illustrate the concept:
The part of the iceberg above water represents our consciousness, that which we are conscious of and for which we can quickly give a response or that for which we don't know the response but know how to find the response.
This iceberg is then separated into two parts that represent our knowledge. On the right is what we know, conscious or not, and the left is what we don't know.
Obviously, the tools used will not be the same depending on the type of problem we are confronted with.
Type 1: We know the solution to the problem. In this case all we need to do is apply the solution
Type 2: We know how to find the solution to the problem. In this case all we need to do is look for the solution.
In general these two cases represent 80% of the problems that we are confronted with. We don't notice them because they are solved quickly. The difficulty is when we are not aware of the solution to a problem. The remaining problems represent 20% of problems.
Unfortunately they take up 80% of our time, as they are more complicated to solve.
Type 3: We do not know the solution, but it is buried in our collective unconscious. I.e. At least one person knows why something is not functionning properly.
In this case we must make people talk, to use the tools that will allow us to dig into our unconscious to find the root cause of the problem. The tools used in this case are the QQOQCP, the 5 W's, brainstorming etc… Tools that make people talk.
The reasoning used in this case is the “Forward” kind of reasoning:
Hypotheses are proposed
These hypotheses are verified against data
Type 4: We do not know the solution and, even after thorough research, we can not find the solution to the problem. Encouraging people to talk is useless in this case, brainstorming is of no use because we simply do not know the answer.
This is where it is necessary to make processes speak, to use the tools that will allow us to dig into the system functions in order to understand the origin of the problem. The tools that we will use here are the multi-vari, the inversion test, design of experiment, etc... Tools that make the process speak.
The reasoning used in this case is the “Backward” type of reasoning:
Data is generated that will reveal the origin of the problem
Hypotheses are proposed
These hypotheses are verified
This reasoning is completely different and we will show, over the course of the following chapter, that it is much more powerful.
The majority of companies waste an enormous amount of time thinking that the problems they are confronted with are of Type 3 while half of them correspond to Type 4. In this case the tools used are not completely inapropriate because they rely on making people speak while they should be making processes speak. The time lost is considerable.
When confronted with a Type 4 problem it is necessary to change your reasoning and use the statistics tools at your disposition to make data speak