Q 574. Problem Definition Tree is an objective method to drill down to project Y (or CTQ) from big Y. What are the rules to make the split from big Y down to the project Y? How should a Black Belt decide which level to stop and finalize the project Y?

 

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To create an effective Problem Definition Tree, a Black Belt should:

• Focus on specific and measurable outcomes.
• Prioritize actionable objectives.
• Maintain logical connections.
• Avoid overlapping or redundant objectives.
• Limit the number of levels.
• Use factual data and evidence.
• Iterate and refine as needed.

When deciding at which level to stop and finalize project Y, a Black Belt should consider:

Project goals and objectives.

• Stakeholder satisfaction.
• Time constraints.
• Budget considerations.
• Change in scope or organizational priorities.
• Clear identification of the problem statement and process improvements.
• Statistical significance.

By considering these factors, a Black Belt can make an informed decision on whether to stop and finalize project Y at a particular level or continue with further improvements.

Problem Definition Tree:

 

 

CTQ Drill down or Problem Definition Tree diagram relates high level focal points(Resultant output)to project objective(factors)

 The measure of those items linked to the CTQ are called Project Y.

 

The following situations mandates the Problem definition Tree to be applied:

 

1.When Project Indication is vague without knowing which parameter need to be improved.

2.When parameters of Big Ys are defined from customer perspective rather than process control perspective.

3.When dimensions of the Big Ys are aimed at abstract terms and not in tangible terms.

 

 

In General ,The following rules can be applied while splitting the Big Ys to Project Y :

 

1st Rule – Boxes in a split should not overlap. Need to respect the parent dictionary and divide it into subgroups

2nd rule – Need to ensure that sub groups selected must encompass the whole dictionary .

3rd Rule – Boxes or sub groups must be able to provide us with details and data needed for running experiments.

 

The Black belt should finalize the last unbreakable activity or component which can contribute to the Big Y and select this item as Project Y. This is the actionable item which need to be acted upon to improve the Project Y and thus the Big Y to solve

 

 

Let us take example of OEE Overall Equipment efficiency not achieved the Target for may '23( Big Y) and drill down to find the project Y - which contributes the highest , so that action can be initiated immediately .

 

The injection  molding machine shop OEE is 84% , which is average of 3 machines OEE #1,#2,#3.However target is 90%.

In this Example - the black belt has to stop here and take a call, after he had broken down the Big Y to actionable items or factor KPIs, at the activities contributing to availability loss of M/C #2 - out of the which Top 3 activity can be taken as Project Ys .Thus we have divided our Big Y of OEE Target not achieved problem into many Project Ys and Black Belt can stop here as below to finalize projects for further working by small work groups on each .

Here Changeover Time is the 1st actionable item to be worked on followed by Breakdown time reduction & material shortage issue reduction. Once all these Project Ys are addressed , eventually the Big Y ( OEE of molding) would be achieved. Problem definition Tree clearly gives us direction, focus.

 

1.Change over time - 45%

2.Breakdown Time - 22%

3.Raw material shortage time - 18%

 

 

The General criteria/steps to be used while splitting boxes.

1.Use Logic to make splits ( using creative & alternate searches)

2.Never move to next level until , all important in the family is identified.

3.Make Broad splits first and detailed splits later - Avoid going into the factor x , until the detailed split of Ys 

4.FInally use facts and physical laws of logical correlation to make decision vis cause/effect matrix.

 

 

Problem definition tree helps to drill down into top areas that are contributors for key business challenges and opportunities. At each level of drill down we need to look at the top contributing factors and further drill down into that area. Problem definition tree also depicts the breakdown of the prospective factors with the suitable explanation for choosing a particular factor at a particular level. Its important to identify all suitable factors contributing at each level of drill down. Each level needs to make sure that it covers the factors that are mutually exclusive to each other. Selection of a factor at a level will be based on the criticality of that factor for the business. Here is an example of problem definition tree. 

 Analysis of the drill down should be stopped when the further drill down do not help to derive business level objectives and starts getting into operational level objectives.

Problem tree is somehow similar to creating mind maps to identify the root cause as well as the downstream effect of a problem in a more structured way. There are a few key rules we should consider to make a decision tree to drill down from CTQ to project big Y. First step is to define the Goal and the to add potential decisions and outcomes. Similar to how you create a Ishikawa diagram using 5 why approach. Once you have the CTQ well defined then you can prioritize the causes/outcomes to act upon. For a black belt to decide when to stop and finalize the Project Y depends on several factors, including the project scope, resources available, and the desired level of improvement. Basically his role is to check & ensure that project Y is aligned to defined goals and we are utilizing all possible resources as per the agreed/defines timelines. Also to track & evaluate the effectiveness of improvement efforts though metrics/kpi’s. If there is any deviation observed by the black belt in any of the above listed factors the project can be stopped or finalized.  

CTQ (critical to quality) tree is one of the six sigma tool to understand the needs of the customer for a product/service and convert them into measurable organizational goals. Big Y is the final goal that is tied to the business strategic goals the project team wants to measure and achieve. Big Y is directly related to customer expectations and requirements and is used to understand and achieve the little Y’s that is tied to the Big Y. CTQ trees are used to identify the critical needs of the customers to provide quality products and service. Important components of the CTQ tree are as follows:

 

1. Identify Customer Needs 

2. List down the Quality Requirement Drivers

3. Prepare Measurable Performance Requirements that each driver should meet to provide quality product

 

Various methods like VOC, VOB, COPQ data, Benchmarking, Focus groups, Financial Analysis of the organization helps identifying the Big Y project. The Big Y project should always be a top down approach so that the team will be able to see a bigger picture that helps to choose which level to stop and finalize the project Y. In DMAIC , Define Phase the Big Y and all the little Ys are identified and defined which are tied to the organization goal.

 

To split the Big Y into little Ys, SMART – Specific | Measurable | Achievable | Relevant & Time bound approach is required. By applying the SMART approach, the Big Y goals can be divided into small Y projects that can help in easy tracking of the project and focus on the timelines to achieve the big Y project. Using the SMART approach, Black belt can choose to stop and finalize the project Y.  Various factors are considered like

 

1.       Customer Needs & Requirements – Basis the Voice of Customer and focus groups and other methods, it is always necessary to understand what customer wants and whether it is aligned to the business goals

2.       Complexity of the project – as multiple stakeholders within the organization are involved, the project shouldn’t be cumbersome and difficult to complete.

3.       Impact of the project – look at the benefit quantification of the project and measure if the objective is aligned to the business goals

4.       Data Availability – Make sure data is available, reliable and measurable

5.       Time Bound – Project should be achievable within timelines to show its results on the business. Longer time the project takes, less its effects on the business and most of the times the long time projects doesn’t fly and due to some or the other reasons they get scrapped. Necessary to meet the desired milestones of the project.

6.       Controls & Risks – Check if there any controls applies to the project and are they within scope and one should evaluate the risks that come with the project and calculate risks to see if they are within acceptable limits.

7.       Project Investment – Before a project is defined and started working towards it, it is always necessary to check if there is any cost involved and is the organization willing to invest that cost to achieve the bigger goal of the organization

If the above requirements are met and aligns to the organization goals, then it is better to finalize the project Y and start working on the project. 

Problem definition tree is graphical tool that represents a problem, its causes and effects. A problem tree has a similar structure to a tree, with the roots representing the causes, the trunk representing the major issue, and the leaves and branches representing the results. It can also be represented in a flow chart format. The Problem being highlighted, all the causes and factors contributing to the problems can be split into small boxes of causes leading to the problem.

 Problem definition tree helps the project team to quickly see how various complex issues interact to create a problem and how this problem develops into a series of repercussions. It shows a means-end relationship.

Problem definition tree helps in:

a.       Planning a project

b.      Helps to identify complex problems and various causes contributing to the problem

c.       Gives a summary of the project plan, other than the problems and causes it also show case the tasks that must be completed, the objective, and the project's results.

Steps and example:

1.       Understand the situation: Analyse what the problem is, why it occurring and what are the factors contributing to the problem. Eg:

2.       Identify the cause: Find out the cause by collecting information, analysing the data and performing root cause analysis. Eg:

3.       Organize the problems in categories so it provides a clear picture of that specific category and doesn’t overlap. Eg.

 

4.       Find the major cause: Decide which issues/problem is the highest contributor and require immediate attention. Further, Drill down the major cause and determine all the factors leading to it. Eg.

             

5.       Once analysed, define a problem statement

Eg. Machine time can be reduced by 60% to realize savings of $60,000

Decision Tree Rules:

1.       Splits should be logical. Be creative and consider alternatives.

2.       Until the most important family is identified, do not move on to the next step

3.       Ideally all but one box on a level can be taken off. If not, search for a new split.

4.       Start with broad splits and go on to more precise splits. It’s better to not test individual X’s until the Solution tree is completed.

5.       We can also make decisions based on facts and physical laws. If we do not have complete data, draw on people’s knowledge to create a Cause-and-effect matrix.

 

Guidelines to split the problems:

a.       The problems should be split into boxes (causes) which are independent of each other and do not overlap. If the causes are overlapped, it will give mixed signals. Example:

 

 

b.      Split must the include everything from the dictionary in the category mentioned in the above and use a common basis for boxes inside a split. Important information might get skipped if the whole dictionary is not represented.  Example.

c.       The split should be Accessible. It must be able to conduct tests and collect data that separates out the rule's boxes. Inaccessible boxes might lead to multiple open branches. Example.

 

 

Problem definition tree

Big y is the goal that is affiliated to the customer requirement. Eg. Improvement in CSAT score,  NPS improvement. Project y are small projects that help achieve the big y. Eg. Customer connect rate, Resolution response TAT, etc

Rules to make the split from big y to project y:

1. Assess the core problem (business goal) post agreement from leadership
2. Write causes in negative form
3. Break them into manageable chunks
4. Validate with existing process and data
5. Weigh the possibilities of success in the existing state
6. If the existing state is not feasible,  then break it down further.

A black belt should be able to arrive at the project Y's simply by comparing the outcomes within each level of drilldown in terms of the effort required and the results expected.

Problem Definition Tree can be used for multiple purposes - a. It is used to identify the project Y from a big Y' b. It is used as a tool to identify the problems, its causes and effects. Here the question specifically asked how it is used for point a. If you have answered for point b, it might not be the right answer, however I have still approved it so that readers can get another perspective on usage of Problem Definition Tree. 

 

The best answer has been provided by Venkateswaran Kazhagamani for providing the correct explanation and also sharing an example. 

 

Note: Starting with this question, we are also checking for AI generated answers. Answers which have more than 15-20% of AI generated content will not be approved. This is the reason that many of the answers have not been approved. Like we always say - you can do your online research but the answer has to be in your words only.