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PROBLEM ANALYSIS TOOLS: FISHBONE DIAGRAM,

MATRIX DIAGRAM AND SCATTER

PLOT DIAGRAM

Presented to

Dr. Betty Polido in partial fulfilmentfor the Subject N414-F

Torreres, Nicel Ann M.Tohoy, Evan Cristy S.

July 3, 2012


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Objectives:

Define fishbone diagram, matrix diagram and scatterplot diagram

Enumerate situations when fishbone diagram or

cause and effect diagram should be used

Differentiate the six shaped matrix diagram

Describe the steps involved in a matrix diagram

Enumerate situation when to use a scatter plot

diagramExplain the scatter plot diagram procedure

Discuss how a fishbone diagram is constructed


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Introduction

Problem analysis tool is useful in solving

problems within an organization, group or team. It

is helpful in citing, analysing and acquiring possiblesolutions to the problem cited. It makes problem

solving and decision making easy and convenient.


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Fishbone Diagram or

Cause and Effect Diagram


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Dr. Kaoru Ishikawa, a Japanese quality control

statistician and a pioneer in quality management,

invented the fishbone diagram. The technique was thenpublished in his 1990 book, "Introduction to Quality

Control."

Therefore, it may be referred to as the Ishikawa

diagram. The fishbone diagram is an analysis tool that

provides a systematic way of looking at effects and the

causes that create or contribute to those effects. Because

of the function of the fishbone diagram, it may bereferred to as a cause-and-effect diagram. The design of

the diagram looks much like the skeleton of a fish.

Therefore, it is often referred to as the fishbone diagram.


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Cause and Effect Diagrams are useful in identifying

and isolating the cause, or the major causes, of a

problem. This diagram lists the problem at one end ofa horizontal line. Diagonal branches are drawn from

this line for each major category of possible causes.

More specific, contributory causes are added to the

branch for each category.

Whatever name you choose, remember that the

value of the fishbone diagram is to assist teams incategorizing the many potential causes of problems or

issues in an orderly way and in identifying root

causes.


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When should a fishbone diagram be used?Does the team...

Need to study a problem/issue to determine the

root cause?

Want to study all the possible reasons why a process

is beginning to have difficulties, problems, or

breakdowns?

Need to identify areas for data collection?Want to study why a process is not performing

properly or producing the desired results?


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How is a fishbone diagram constructed?Basic Steps:

1. Draw the fishbone diagram.

2. List the problem/issue to be studied in the "head of the

fish".3. Label each ""bone" of the "fish". The major categories

typically utilized are:

The 4 Ms:

Methods, Machines, Materials, ManpowerThe 4 Ps:

Place, Procedure, People, PoliciesThe 4 Ss:

Surroundings, Suppliers, Systems, Skills


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Note: You may use one of the four categories suggested,

combine them in any fashion or make up your own. The

categories are to help you organize your ideas.4. Use an idea-generating technique (e.g., brainstorming)

to identify the factors within each category that may be

affecting the problem/issue and/or effect being studied.The team should ask... "What are the machine-issues

affecting/causing..."5. Repeat this procedure with each factor under the

category to produce sub-factors. Continue asking, "Why is

this happening?" and put additional segments each factor

and subsequently under each sub-factor.


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6. Continue until you no longer get useful information

as you ask, "Why is that happening?"7. Analyze the results of the fishbone after team

members agree that an adequate amount of detail

has been provided under each major category. Do this

by looking for those items that appear in more than

one category. These become the 'most likely causes".8. For those items identified as the "most likelycauses", the team should reach consensus on listing

those items in priority order with the first item being

the most probable" cause.


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Example of a Fishbone or Cause and Effect Diagram
http://www.mindtools.com/pages/article/Cause-Effect-Diagram-Example-3.htm


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Matrix Diagram or Quality

Function Deployment


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The matrix diagram or quality function deployment

shows the relationship between two, three or fourgroups of information. It also can give information

about the relationship, such as its strength, the roles

played by various individuals or measurements.

Six differently shaped matrices are possible: L, T, Y,

X, C and roofshaped, depending on how many

groups must be compared.


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When to Use Each Matrix Diagram Shape

In the examples, matrix axes have been shaded to

emphasize the letter that gives each matrix its name.

An Lshaped matrix relates two groups of items to

each other (or one group to itself).

A Tshaped matrix relates three groups of items:

groups B and C are each related to A. Groups B and Care not related to each other.
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A Yshaped matrix relates three groups of items.

Each group is related to the other two in a circularfashion.

A Cshaped matrix relates three groups of items

all together simultaneously, in 3-D.

An Xshaped matrix relates four groups of items.

Each group is related to two others in a circular

fashion.

A roofshaped matrix relates one group of itemsto itself. It is usually used along with an L or T

shaped matrix.
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L-shaped 2 groups A B (or A A)

T-shaped 3 groups B A C but not B C

Y-shaped 3 groups A B C A

C-shaped 3 groups All three simultaneously (3-D)

X-shaped 4 groups A B C D A but not A C

or B D

Roof-

shaped

1 group A A when also A B in L or T

Table 1: When to use differently-shaped matrices


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Frequently Used Matrix Diagram Symbols


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The L shape and T shape matrix are the most

commonly used matrix diagrams. Matrix consists ofrows and columns. The columns are used for

representing sub-categories of one variable and the

rows represent sub-categories of the second

variable. These two variables should have a

relationship. The matrix brings down the correlation

between the two variables.


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Steps involved in a Matrix Diagram

1.Select the problem.

2.Form a team with 4-5 people.

3.Choose a facilitator for the coordination of the teamsactivities.

4.Determine the product or process variables to be studied.

5.Decide on the matrix shape based on task.

6.Place the information in the matrix.

7.Draw the lines of the matrix.

8.Determine the symbols to be utilized for representing degree

of relationship between the variables and also include a

legend for symbol definitions.

9.Enter the symbols into the correct cells depending on their

relationships.

10.Analyze.


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The advantage of a matrix diagram is that ithelps in presenting complex information in easily

understandable form. It is important to study and

understand the relationships for the decision making

process. This will help clarify the relationship between

factors involved.


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Scatter Plot

Diagram


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The scatter diagram graphs pairs of numerical

data, with one variable on each axis, to look for a

relationship between them. If the variables arecorrelated, the points will fall along a line or curve.

The better the correlation, the tighter the points will

hug the line.

When to Use a Scatter Diagram

When you have paired numerical data.

When your dependent variable may have multiple

values for each value of your independent variable.


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When trying to determine whether the two variables

are related, such as

When trying to identify potential root causes ofproblems.

After brainstorming causes and effects using a

fishbone diagram, to determine objectivelywhether a particular cause and effect are related.

When determining whether two effects that

appears to be related both occur with the samecause.

When testing for autocorrelation before

constructing a control chart.


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Scatter Diagram Procedure

1. Collect pairs of data where a relationship is suspected.

2. Draw a graph with the independent variable on thehorizontal axis and the dependent variable on the vertical

axis. For each pair of data, put a dot or a symbol where

the x-axis value intersects the y-axis value. (If two dots fall

together, put them side by side, touching, so that you can

see both.)

3. Look at the pattern of points to see if a relationship is

obvious. If the data clearly form a line or a curve, you may

stop. The variables are correlated. You may wish to use

regression or correlation analysis now. Otherwise,

complete steps 4 through 7.


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4. Divide points on the graph into four quadrants. If

there are X points on the graph,

1.Count X/2 points from top to bottom and draw a

horizontal line.

2.Count X/2 points from left to right and draw a

vertical line.

3.If number of points is odd, draw the line through

the middle point.

5. Count the points in each quadrant. Do not count

points on a line.


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6. Add the diagonally opposite quadrants. Find the

smaller sum and the total of points in all quadrants.

A = points in upper left + points in lower rightB = points in upper right + points in lower left

Q = the smaller of A and B

N = A + B

7. Look up the limit for N on the trend test table.

1.If Q is less than the limit, the two variables are related.

2.If Q is greater than or equal to the limit, the pattern

could have occurred from random chance.


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Scatter Diagram Example


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Scatter Diagram Considerations:

Even if the scatter diagram shows a relationship, do notassume that one variable caused the other. Both may be

influenced by a third variable.

When the data are plotted, the more the diagram resembles

a straight line, the stronger the relationship.If a line is not clear, statistics (N and Q) determine whether

there is reasonable certainty that a relationship exists. If the

statistics say that no relationship exists, the pattern could

have occurred by random chance.

If the scatter diagram shows no relationship between the

variables, consider whether the data might be stratified.


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If the diagram shows no relationship, consider

whether the independent (x-axis) variable has beenvaried widely. Sometimes a relationship is not

apparent because the data dont cover a wide

enough range.Think creatively about how to use scatter diagrams

to discover a root cause.

Drawing a scatter diagram is the first step in looking

for a relationship between variables.


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Lessons Learned:

When we have a serious problem, it's important to

explore all of the things that could cause it, before we start tothink about a solution. That way we can solve the problem

completely, first time round, rather than just addressing part

of it and having the problem run on and on. This is where the

problem analysis tool comes out. It is of major importancewith regard to solving problems within an organization, group

or team. After all discussion and clarification of the tools, all

problems and decision making will be much easier to deal and

convenient to use. It is important to determine whether thedifferent groups of people perceive the problem in the same

way in order for them to utilize the appropriate tool in

acquiring possible solutions.

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