1. Tree diagram Pareto Matrix diagram Check sheet Defect location map
Drill Down Tools
Tree diagram
Pareto
Matrix diagram
Check sheet
Defect location map
This lesson presents several tools that will help you focus your attention on promising categories and drivers. The tools covered are THE TREE diagram, PARETO ANALYSIS, MATRIX DIAGRAMS, CHECK SHEETS and DEFECT LOCATION maps. Some of these tools have been covered in earlier lessons, but they are also use at this point in the measure phase. The way they are used is somewhat different than in the define phase.

2. Copyright © 2008 by Thomas Pyzdek
Tree Diagram
At this stage you will use tree diagrams to focus your project in additional detail
Circuit boards not available
Tree diagrams have already been covered in develop project plan (determine drivers.) However, they are useful once again at this point in the project. Here’s an illustration that starts at the top in the Define stage, where the leadership decided to address customer complaints. From this very high level the leadership team has drilled down several levels until finally assigning a Black Belt a PROJECT TO WORK: circuit boards not available. AS THE PROJECT Black Belt you will use the tree diagram to drill down even further. Of course, you will be using data to quantify these drivers at each step.
Your project
Additional drill- down
Copyright © 2008 by Thomas Pyzdek

3. Copyright © 2008 by Thomas Pyzdek
Pareto Analysis
Pareto analysis was introduced when you chose the project
Use it again here to drill down further
Keep drilling until it’s logical to stop–this is where you will begin the analyze phase
PARETO ANALYSIS is another tool used in the Define phase and re-used here. Here’s an example. The leadership team wants to reduce customer complaints. A Pareto analysis reveals that the #1 type of customer complaint is “slow service.” YOU CAN DRILL down further by collecting data on the drivers of slow service and presenting these results in another Pareto diagram showing the number of times slow service was traceable to each driver. YOU CAN CONTINUE to create drill-down Pareto diagrams until you reach a point where it makes sense to stop. Identifying this point is a matter of judgment. When you reach this point you will be ready to move into the analyze phase where you will model the relationship between the driver and it’s root causes. ?
Copyright © 2008 by Thomas Pyzdek

4. Using Trees with Pareto Analysis
Use the tree diagram to identify a set of drivers
Use Pareto to analyze the relative size of the drivers
Candidate for drill down Pareto analysis
You can also “mix and match” the various tools. FOR EXAMLE, you could use tree diagrams to drill down to a set of drivers, THEN USE PARETO analysis to compare the magnitude of the different drivers.
Copyright © 2008 by Thomas Pyzdek

5. Matrix Diagram
Systematically evaluate the relationship between two groups of ideas
Can be used in conjunction with decision trees
Use lowest level of decision tree as the contents of rows and columns
One dimension of analysis
Matrix of Relationships
Another dimension of analysis
Another useful tool for identifying and prioritizing drivers is the matrix diagram. Matrix diagrams are two dimensional tables that show how two different dimensions of a problem relate to one another. MATRIX DIAGRAMS can be used with decision trees by LETTING THE lowest level of the decision tree populate the rows and columns of the matrix.
Copyright © 2008 by Thomas Pyzdek

6. Tree Diagrams  X-Y Matrix 
-High impact
-Moderate impact
-Low impact
-Increases problems
-Decreases problems     
Here’s an example of using matrix and tree diagrams together. Assume that reducing customer complaints with the fulfillment and delivery process is a leadership goal and that the leaders have identified three drivers of customer complaints. Here’s the tree diagram for this. Each of the lowest elements in the tree diagram corresponds to a column in the matrix diagram. THERE ARE FOUR activities in the process, these are shown here. Each process activity corresponds to a row in the matrix. NOW WE WILL determine the relationship between each row and column element. In other words, we will assess the impact of the process activity on the particular type of complaint. HERE WE SEE that the team believes that the order taking process has a high impact on billing complaints and a moderate impact on late delivery complaints. THIS IS REPEATED for all of the rows and columns. BY LOOKING AT the impacts for each process activity the team can determine where to focus their efforts, or which process activity to address first. OF COURSE, in Six Sigma work we usually don’t accept judgments as the final word. Data must be obtained in the analyze phase to validate the judgments.
Identify which process activities have the most impact
Data will be used to validate these judgments
Copyright © 2008 by Thomas Pyzdek

7. Example of Matrix Diagram
Process activities
Items essential to quality patient care
THE MATRIX DIAGRAM can also be used by itself to assess the relationship between two dimensions. This matrix diagram shows that you can enhance your matrix diagrams with various rows, columns, weighting schemes and so on. I should caution however that it’s easy to get carried away with these enhancements. Try to keep things as simple as possible while still getting the job done.
Copyright © 2008 by Thomas Pyzdek

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Check Sheets
Tool consisting of items and an indicator of how often the item occurs
Make collection of new data easier
Designed to answer a question
“Has all work been done?”
“Have all inspections been completed?”
“Are all tasks completed satisfactorily?”
“Are there more problems of one type than another?”
Reminders that direct the attention of the data collector
Often used in conjunction with other tools
One of the first quality engineering workshops I attended was taught by an engineer working on the first space shuttle. He told us that the shuttle launch had been in danger of delays because the shuttle’s electrical panels were repeatedly failing inspections. The panel assemblers were told to use check sheets to confirm that they had double-checked their work. After this simple change, no more inspections failed.
Check sheets are a deceptively simple tool that is a list of items and some indication of how often the item occurs. CHECK SHEETS are a useful data collection tool when your database doesn’t include the information you need for your project. THEY CAN BE USED to answer several important questions, such as has all of the work been done? HAVE ALL required inspections been completed? ARE ALL TASKS completed satisfactorily? Or WHAT IS THE frequency of problems of given types? CHECK SHEETS serve to remind the data collector or inspector of what things to look for. THEY ARE often used in conjunction with other tools, such as Pareto diagrams, histograms or tree diagrams. In this capacity they help quantify observations to validate judgments.
Copyright © 2008 by Thomas Pyzdek

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Process Check Sheet
Constructed using several ranges of measurement and recording a mark for each observation in a range
Resembles a histogram
There are several variations on check sheets. One of these is the process check sheet which is used to keep track of measurements from a process. It is created by creating several cells covering a range of measurements. As a measurement is taken, a mark is made in the appropriate cell. The resulting check sheet looks similar to a histogram and provides a quick look at the process distribution. These check sheets are usually made on the spot in real time to get a sense of how the process is performing. They’re useful when teams are performing on site investigations. Have each team member track one or more measurements and you can obtain a wealth of information in a very short time.
Copyright © 2008 by Thomas Pyzdek

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Defect Check Sheet
Here the different types of defects are listed and the observed frequencies observed. Resembles a bar chart
Defect check sheets are similar to process check sheets, except they are made from categorical data instead of from continuous scale measurements. The pattern of the tick marks is similar in appearance to a bar chart. They are used on the same sorts of applications as process check sheets.
Copyright © 2008 by Thomas Pyzdek

11. Stratified Defects Check Sheet
Stratify a particular defect type according to logical criteria
Stratified defects check sheets are two dimensional check sheets. They are a graphical variation of matrix diagrams. They are used to examine two categories of interest simultaneously. It’s usually possible to get the basic information from such check sheets at a glance, providing you with a set of hypotheses to test by performing additional analysis.
Copyright © 2008 by Thomas Pyzdek

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Defect Location Map
Maps made from drawings, photos, etc. that show where problems occur
As the saying goes, sometimes a picture is worth 1,000 words. Defect location maps take advantage of the brain’s ability to discern patterns from pictorial representations by using pictures, drawings, building layouts, floor plans, blueprints and other graphical displays to record information. Defect location maps can, of course, be used to record information other than defects, such as accidents, places where people congregate, et cetera.
Copyright © 2008 by Thomas Pyzdek

13. End of Lesson