Tree Diagram

Will Six Sigma Be Relevant For The Future
  • A Tree Diagram is a chart that begins with one central item and then branches into more items and keeps branching until the line of inquiry begun with the central item has been exhausted.
  • You will progress from left to right with the highest order objects / most relevant concepts on the left. You'd start with the "whys" and work your way to the "hows." You may also begin with the "goals" and work your way down to the "means" of achieving those goals.
  • This is a helpful tool to outline details relating to a problem, idea, process or a plan.

When to use a Tree Diagram?

  • When a problem is well-understood or addressed in broad terms, you need to get into specifics, such as creating logical steps to achieve a goal
  • When creating a solution or another strategy into action
  • When it comes to a detailed analysis of processes
  • When you're looking for the root cause of a problem
  • When analyzing the pros and cons of various possible solutions
  • After the main issue has been identified using an affinity diagram or an interrelationship diagram
  • To explain data to others as a communication tool

Tree Diagram Procedure

  • Make a statement about the target, project, problem, or whatever is being studied.
    - Write it at the top of the work surface (for a vertical tree) or far left (for a horizontaltree).
  • Ask a follow-up question to get to the nextlevel of information.
    - For example, if you're working on a goal, an action plan, or a work breakdown structure, ask yourself, "What tasks must be completed to achieve this?" or "How can this be achieved?" For root-cause analysis, enquire: "What causes this?" "Why does this happen?" or "How does this happen?"
  • Make a list of all possible solutions. Ideas may be derived from an affinity diagram or an interrelationship diagram that has been completed previously.
    - Each idea should be written on a separate line underneath (for a vertical tree) or to the right of (for a horizontal tree) the first statement. Show ties between the levelswith arrows.
  • Do a "necessary and sufficient" check. Is it true that all of the items on this level are required for the item on the level above?
    - Will all of the items on this level be adequate for the one on the previous level if they were all present or completed?
  • The topic of each of the new concept statements is now a target, objective, or problem statement. Ask the question again for each one to get to the next level of detail. Create a new tier of statements and use arrows to display the connections to the previous tier of ideas.
    - Do a "necessary-and-sufficient" check for each set of items.
  • Continue to turn each new idea into a subject statement and ask the question. Continue until you reach fundamental elements: specific actions that can be taken to find the root causes.
  • Do a "necessary-and-sufficient" check of the entire diagram. Are all of the elements needed to achieve the goal? Will it be sufficient if all of the elements were present or accomplished to achieve the goal?