Analyze
Tools to help you analyze the root cause of the variations
5 Whys
5 Whys is an iterative interrogative technique used to explore the cause-and-effect relationships underlying a particular problem. The primary goal of the technique is to determine the root cause of a defect or problem by repeating the question “Why?” five times.
How to use it and helpful resources:
- Invite all affected or touched by the process.
- Ask the first “why?” to the problem statement you are trying to solve
- Continue asking “why”? up to five times. It can be asked less than five, but usually any more than five can get you in the weeds of the issue.
- Assign any action items in need of follow up.
- Communicate results to the team.
Instructional videos:
Fishbone Diagram
The fishbone diagram identifies many possible causes for an effect or problem by sorting ideas into useful categories.
How to use it and helpful resources:
- Brainstorm the major categories of causes of the problem and write the categories as the main “buckets”.
- Brainstorm all the possible causes of the problem within those buckets.
- Continue to ask “why does this happen?”
- When the group runs out of ideas, focus on areas that have the most issues to determine a root cause.
What is a Fishbone Diagram or Ishikawa Cause and Effort Diagram?
Instructional videos:
Pareto Chart
A pareto chart is a type of chart that contains both bars and a line graph, where individual values are represented in descending order by bars, and the cumulative total is represented by the line.
How to use it and helpful resources:
Create a Pareto Chart in Excel
Instructional videos:
Interrelationship Diagram
The interrelationship diagram shows cause-and-effect relationships. Its main purpose is to help identify relationships that are not easily recognizable.
How to use it and helpful resources:
- Select or define the problem.
- Identify issues, influences, or causes.
- Determine how they are connected.
- Distinguish between causes and symptoms.
- Prioritize problem areas discovered.
Instructional videos:
Design of Experiments
Design of experiments (DOE) is defined as a branch of applied statistics that deals with planning, conducting, analyzing, and interpreting controlled tests to evaluate the factors that control the value of a parameter or group of parameters. DOE is a powerful data collection and analysis tool that can be used in a variety of experimental situations.
How to use it and helpful resources:
Design of Experiments in Six Sigma
Instructional videos:
Spaghetti Diagram
A spaghetti diagram is used to map physical movement and defined as a visual representation using a continuous flow line tracing the path of an item or activity through a process. The continuous flow line enables process teams to identify redundancies in the workflow and opportunities to expedite process flow.
How to use it and helpful resources:
- Map the area you want to analyze.
- Number everything involved in the process.
- Draw lines for every movement within the process.
- (optional) Measure the distance between each movement and the time it takes to move from one area to the other.
Instructional videos:
Scatter Plot Diagram
A scatter plot (also known as a scatter chart or scatter graph) uses dots to represent values for two different numeric variables. The position of each dot on the horizontal and vertical axis indicates values for an individual data point. Scatter plots are used to observe relationships between variables.