Identifying the Root Cause Using the Tree Diagram

The tree diagram is an excellent tool to use in identifying the root cause of a nonconformance. I believe that any individual involved in the investigation of a nonconformance has his/her preferences as to which tool enables them to get the job done in an efficient and effective manner. For me, some of the benefits of the tree diagram can be summarizes as follows:
1. It clearly lays out the full range of the problem that you are investigating in a systematic, and visually expressive manner. By that I mean, you don’t have to read through multiple layers of jargon to sift out the problem. It is clearly stated in the diagram and you can clearly see how each cause is related to the problem statement simply by following the flow chart.
2. It helps to create focus around the core problem. Oftentimes, investigating teams tend to drift off the core problem they are investigating and begin to discuss other issues that are loosely connected to the problem under investigation.
3. It’s simple. The simplicity of the tree diagram begins with defining the problem statement and then connecting the dots, if you will, by asking the question “why”.
Steps to constructing the perfect tree diagram:
1. Assemble the right core team members
· The selection of team members plays a key role in the effectiveness of the group in investigating the root cause of a given nonconformance.
· You want to be sure that the members of the team are knowledgeable about the problem and can contribute to the discussions
2. Define the problem
· “A problem well stated is a problem half solved” C. Kettering. You need to ensure that the problem is clear, gets to the point of “what is wrong with what,” and is free from conclusions.
3. Construct the tree diagram
· The best tool to use is Microsoft Visio where you can click and drag the boxes onto the sheet
· With the problem statement listed in the “trunk” of the tree, you then construct the branches where you answer the question of “why”
· Remember, you are asking “why” and not “who.” One of the biggest problems that I see in my line of work training others in conducting effective root cause investigations is that they often want to answer “who” as opposed to “why”. I always stress in my trainings that it is not so much about the people, the “who” as it is about the process. If your process is ill-defined, undefined, or otherwise non-existent, it does not matter “who” is running the process. The process is broken and requires fixing.
4. Validate the diagram
· Have your diagram scrutinized by someone intimately knowledgeable about the process but was not part of the core team investigating the nonconformance.
· Ask this individual to review the diagram for completeness and accuracy. Make changes as appropriate
5. Identify the root cause
· Review the completed tree diagram and identify those issues where process improvements are required.
· The issues listed at the end of the “why” branch are often the ones that will identify the root cause of the problem. These are often process-related issues and are where you will get the “biggest bang for your buck.”

Keeping the Focus on Key Problems

At any given day, a manufacturing or production environment will experience a myriad of problems with different levels of risk or urgency. Determining which problems require further investigation and resolution is a challenge faced by many well-meaning managers. The good news, however, is that there are a few tried and true tools of the trade that may be used to help identify and focus on key problems that require quick resolution. The first tool is:
1. Pareto Chart
Pareto chart is a great tool to use when your goal is to focus in on the problems which offer the greatest potential for improvement. In its simplest form, a Pareto chart is a bar graph chart showing the relative frequencies of each issue under evaluation and showing the relative frequencies. Pareto charts will show you the relative importance of problems in a simple, easily interpreted and visual format. This tool is excellent in helping the team remain focused on issues with the greatest impact that will provide the highest yield. I like to say that it is the tool that shows you where you will receive the “biggest bang for your buck”.
Oftentimes, management can become so overwhelmed by the many issues plaguing their departments that they will put valuable resources (i.e., time, personnel and financial) on several insignificant issues while the more pressing issues remain untouched and unresolved. The Pareto principle states that “20% of the sources cause 80% of the problem”. Therefore, it is imperative that you have a methodology to evaluate the many problems facing the department and focusing in on the top 20% or even top 10% which causes 80% of your problems.
Next week’s blog, I will cover how to effectively perform a Pareto on a given problem. Happy Investigating!

Problem Solving Tool Selection

Previously, I discussed some key elements to Problem Solving involving the analysis of several key components of root cause determination in order to effectively solve the problem. Namely, an Accurate Determination of the Problem, Selecting the Appropriate Problem Solving Tool(s), and an analysis of when to use each tool. Here, I will provide you with 3 additional tools that may be used in order to effectively determine the root cause of a given nonconformance:

1. Affinity Diagram
Affinity diagram is another great tool to use because it allows the team to brainstorm a significant number of ideas relating to an issue and then group and summarize them in order to fully understand the essence of the problem, hence the solutions. I like to use Affinity Diagrams as a problem solving tool because it gives each team member the opportunity to be completely open to ideas that one may not necessarily be aware of. It is also a great tool for overcoming team stagnation.

2. Check Sheet
Check Sheets are best used in counting and accumulating data associated with a process. It allows team members to systematically record and compile data in order to effectively identify trends. This compilation of data creates a clear picture of the elements of the process and allows patterns in the data to become clearly and quickly evident.

3. Histogram
Histogram is a great tool to use in summarizing data from a process over a period of time. This data is then graphically presented in bar form showing the frequency distribution. Histogram is a great tool to use when you want to display large amounts of data in tabular form. This may prove to be of great benefit because graphical representation of data may sometimes be difficult to interpret and having this data represented in a tabular format renders it more easily understood. Histogram also quickly illustrates the underlying distribution of the data which in turn may provide useful information for predicting future process performance. Which tool to use? Depends on the nature of the nonconformance. Happy Investigating!

Elements of Problem Solving

Problem Solving or Root Cause determination requires the analysis of several key components in order to effectively solve the problem. Here are 3 elements of the key components:

1. An Accurate Determination of the Problem
“A problem well stated is a problem half solved” Charles Kettering (American engineer, inventor of the electric starter, 1876-1958). The criticality of clearly identifying the problem statement is that it helps you (and your team members) to maintain razor-like focus on the issue at hand. There is a tendency to wander outside of the scope of the problem you are investigating once team members become involved. Therefore, it is important that all team members work diligently on clearly identifying the problem at hand and work as a cohesive unit to determine the root cause.

2. Selecting the Appropriate Problem Solving Tool
There is a multitude of problem solving tools/methodologies out there for analyzing a problem. Often, team members are not well-versed in the different tools and when it is appropriate to use them. As a result, they will use a tool that may not be the best fit and end in long discussions around symptoms of the problem but never arriving at an accurate root cause determination. Some of the more popular tools/techniques are as follows:
i) Brainstorming
ii) Cause and Effect Diagram (a.k.a Fishbone Diagram)
iii) Tree Diagram

3. When to Use it?

i. Brainstorming is often used as a primary means of establishing a means for the team to generate numerous ideas as to why an event occurred. Team members throw out ideas in a non-judgmental and encouraging atmosphere. This encourages “open thinking”, enthusiasm, and creativity.

ii. Cause and Effect Diagram (a.k.a Fishbone Diagram) this tool is often used to explore issues that are multi-factorial in nature and help team identify causes of the problem as opposed to symptoms of the problem. It enables team members to focus on the problem, identify the various elements that may contribute to the problem, and builds consensus.Tree Diagram displays the issue at hand and its related causes in a flow chart format that continues to ask the question “why”. It helps team members focus on issues contributing directly to the problem. Team members are able to graphically evaluate the causes of the problem, investigate and systematically arrive at a root cause.

iii. Tree Diagram displays the issue at hand and its related causes in a flow chart format that continues to ask the question “why”. It helps team members focus on issues contributing directly to the problem. Team members are able to graphically evaluate the causes of the problem, investigate and systematically arrive at a root cause.

Marie

Determining appropriate corrective actions

In any root cause investigation of a product or quality system nonconformance, the ability to determine the appropriate corrective actions can mean the difference between an effective CAPA that successfully addresses the issue and an ineffective CAPA that is doomed to be repeated. Too often, investigators, either in a rush to complete the investigation by its due date, or as a result of a lack of experience, may determine actions that are not appropriate in addressing the root cause of the nonconformance.

It is a given reality that root cause investigations must be completed in a timely manner and corrective and preventive actions must be implemented and verified in order to prevent recurrence of this event. However, compliance to the timeliness of an investigation and determining appropriate corrective actions do not have to be an “either / or” situation. It is possible to complete the investigation within the allotted time and identify appropriate corrective actions to prevent recurrence. Here’s how:

1- Develop an investigation plan at the onset of the investigation and ensure that each person with responsibilities are held accountable for meeting due dates. Why is this step important? Too often, investigations fail to meet its due date not due the complexity of the event, but rather, due to a lack of planning. Remember the old adage: “if you fail to plan, then you plan to fail.” This axiom holds true in the investigation world as well. The significance of an investigation plan is that it is a tool which aids in the tracking and planning of activities and it monitors actions toward completion. This visual aid, if you will, helps keep everyone on the same page and moving towards a unified goal.

2- Ensure that the action address the root cause of the nonconformance and not a symptom. This means that you must drill down to the core of the issue by brainstorming all probable causes and not simply stop at the first cause which “seems” most likely. Drilling down also means gathering input from other applicable SMEs or affected group members to ensure that brainstorming sessions are productive and that all possible scenarios have been evaluated.

3- Verify that the actions are effective in producing the anticipated outcome. On many occasions I have seen investigators come up with proposed actions that either do not address the root cause or are not executable for a variety of reasons. The act of verification may entail communicating with other impacted departments to determine whether the proposed solution may be implemented by the other group. I like to call this “a dry run”. The time to figure out whether an action will work is not during the roll out or implementation phase. A bit of pre-planning can spare you months of aggravation and possibly, another instance of a reportable nonconformance.

Four Simple Steps

In my last blog I discussed the importance of drilling down to the root cause in any nonconformance investigation and how to distinguish between a root cause and a contributing cause. In today’s blog, I will discuss four simple phases in the investigation process to follow once you have identified your root cause that will ensure a thorough investigation and effective corrective and preventive actions.

1. Plan
Once the root cause of the nonconformance has been identified via a thorough investigation, a plan must be identified that will effectively eliminate the root cause for this event. This plan must take into account all of the outcomes from the investigation; i.e., “what broke down?” or “what failed to occur?” The plan must evaluate each of the areas of noncompliance and with input from appropriate subject matter experts, identify a strategy by which each of the identified deficiencies will be remediated.

2. Verify / Validate
Once the plan has been developed, it must be verified / validated to ensure that the action(s) as identified will in fact correct the issue. This step is essential because it provides you with critical information early in the process that will alert you of potential gaps/flaws in your proposed plan. This may include gaps related to lack of resources, ambiguous interpretation / wording, or unrealistic expectations, to name a few. This early notification step allows you to make necessary modifications to a proposed plan that may not be executable as initially projected.

3. Implement
Once the plan has been finalized and approved, the actions have been verified / validated, it is now time to implement the changes. With implementation comes proper documentation to ensure that all affected parties have been appropriately notified, the necessary trainings have occurred, and there is evidence to show that the training is effective.

4. Monitor
This final phase of the process is not only a critical one but also one that is often overlooked by many well meaning quality investigators. The monitoring phase is important because it allows you to see (in real time) how effective your actions have been. Many people falsely conclude that because an activity/ action have been “validated” then it must be effective. This is clearly not the case. Validation is simply “confirmation by examination and provision of objective evidence that the particular requirement for a specific intended use can be consistently fulfilled.” Unfortunately, once that validated activity enters the production environment, deviations may occur resulting in the reporting of a nonconformance.

Investigating Cause – Drilling down to the root cause

In any nonconformance investigation, identifying the root cause is an integral part of the process. Identifying the root cause enables one to:

*Implement effective corrective actions
*Accurately trend data for process monitoring
*Implement effective preventive actions
* Develop effective strategies for continuous improvement

With so many different benefits of identifying the root cause of a nonconformance, it is imperative that the investigator does his/her due diligence to ensure that appropriate measures are taken.

One of the biggest challenges that various pharmaceutical / medical device companies face is that oftentimes, investigations stop at the first, immediate cause and fails to drill down further to address the systemic underlying cause(s). Or, their investigation may identify several contributing causes but fails to identify the root cause of a nonconformance. How can you tell the difference between a contributing cause and a root cause? Experience, Experience, Experience!

Experience is a critical factor in any comprehensive root cause investigation of an identified nonconformance. The key to differentiating between a contributing cause and a root cause lies with:

1. Experienced Investigators—they are an integral part of the process in that they are able to bring rational, sound judgment to the table. They have intimate knowledge of what works, what does not work and what requires improvement. They are not prone to “shoot at the hip” and stop the investigation after they have answered the first “why” an event occurred.

2. Experienced Mentors—coupled with an experienced investigator, experienced mentors are crucial in bringing unbiased, thorough, and systematic approach to a nonconformance investigation. They help the experienced investigator drill down even further into their process and to identify potential gaps and areas for process improvement.

3. Experienced Quality Oversight—The Quality dept. must give final approval of any nonconformance investigation and this individual must possess the necessary education, knowledge and experience in order to effectively carry out this quality function. Quality is the final reviewer of the investigation and as such, an experienced Quality reviewer will bring to the table a fresh viewpoint that ensures the comprehensiveness of the investigation.