Help Manual


Sigma Magic Help Version 15

Tree Diagram


A Tree Diagram is used to break up a big problem into a well-defined smaller scope problem and it helps explain the logic of the problem breakdown so others can understand how the problem was selected. This tool can be used to help select a well-defined project and identify the scope of a project before developing the project charter.

This tool can be added to your active workbook by clicking on Project and then selecting Tree Diagram.


Click on Analysis Setup to open the menu options for this tool.


A sample screenshot of the setup menu is shown below.
Input Dialog Box
Num Rows: Specify the number of rows for the problem definition tree. Each row is used to split the decision tree by one level.
Num Cols: Specify the number of cols for the problem definition tree. Each col is used to break out the number of branches at a given level. Find out the maximum number of branches across all rows and use that number here.
View Example: Click on this button to open the example file. You can view the example to get an idea of how to fill out this tool or you can use the example as a starting point and modify it to meet your project needs.
Help Button: Click on this button to open the help file for this topic.
Cancel Button: Click on this button to cancel all changes to the settings and exit this dialog box.
OK Button: Click on this button to save all changes and compute the outputs for this analysis.


Enter the following data in the worksheet:
  • Enter the information for the Basis of Split, the breakdown for each level, and the reason for selecting a particular branch of the "Tree".
  • Once the tree diagram is complete, the updated problem statement needs to be written at the bottom based on the items that were not crossed out in the Tree diagram.


If you click on the Checklist button, you will see the following dialog box. Checklist The checklist contains a few pointers on things you need to pay particular attention to while performing this analysis. The checklist has been derived from experience working on past projects. Not all the checklist items need to apply to you. However, you should carefully review the checklist and apply any recommendations that make sense for your project. Make sure to read each checklist item and mark it as completed after you have read and taken actions as appropriate for your project.


If you click on the Verify button, the software will perform some checks on the data you have entered. A sample screenshot of the dialog box is shown in the figure below. Verify The objective of this analysis as well as any checks that are performed is listed in this dialog box. For example, the software may check if you have correctly specified the input options and entered the required data on the worksheet. The results of the analysis checks are listed on the right. If the checks are passed, then they are shown as a green-colored checkmark. If the verification checks fail, then they are shown as a red-colored cross. If the verification checks result in a warning, they are shown in the orange color exclamation mark and finally, any checks that are required to be performed by the user are shown as blue info icons.


Click on Compute Outputs to update the output calculations. A sample screenshot of the worksheet is shown below. outputs If there are no issues with the worksheet (as determined by how you answer the questions on the following dialog) then the Conclusion box states that the analysis is okay. If not, it will report that there are some issues with the analysis that has to be fixed.


Here are a few pointers regarding this analysis:
  • Tree Diagrams are used to determine the scope of your project and to explain the scope logic to others and get their buy-in. You need to use as many levels as needed to drill down to a problem statement that is small enough that you can finish the project in a reasonable time and at the same time large enough to be able to provide sufficient benefits to the company.