After World War II, Japan adopted quality as an economic strategy and selected seven statistical tools to analyze quality problems and drive continuous improvement. The seven tools - Pareto charts, cause-and-effect diagrams, histograms, control charts, scatter plots, check sheets, and flow charts - can identify up to 95% of issues. Each tool has a specific purpose, such as prioritizing problems with Pareto charts or identifying relationships between variables with scatter plots. Using these tools, Japanese companies were able to dramatically improve quality and economic performance.

1. 7 QUALITY CONTROL
TOOLS
By
Vima Mali

2. INTRODUCTION
The 7 QC Tools are simple statistical tools used for
problem solving.
These tools were either developed in Japan or
introduced to Japan by the Quality Gurus such as
Deming and Juran.
 In terms of importance, these are the most useful.
Kaoru Ishikawa has stated that these 7 tools can be
used to solve 95 percent of all problems.
These tools have been the foundation of Japan's
astomishing industrial resurgence after the second
world war.

3. Cost of Quality
1. Prevention costs
2. Appraisal costs(Companies pay appraisal costs as part
of the quality control process to ensure that their
products and services meet customer expectations and
regulatory requirements.)
3. Internal failure costs
4. External failure costs
5. Opportunity costs

4. Quality Improvement
Traditional
Time
Quality

5. Continuous improvement philosophy
1. Kaizen: Japanese term for continuous improvement.
A step-by-step improvement of business processes.
2. PDCA: Plan-do-check-act as defined by Deming.
Plan Do
Act Check
3. Benchmarking

6. What is total Quality management?
A core definition of total quality management
(TQM) describes a management approach to
long–term success through customer
satisfaction.
In a TQM effort, all members of an organization
participate in improving processes, products,
services, and the culture in which they work.

7. After World War II the Japanese adopted 'quality' as a
philosophy for economic recovery and, in line with this
traditional approach, sought seven tools to accomplish the
economic rejuvenation. The seven tools chosen were
For solving quality problems following seven QC tools are
required
1. Pareto Diagram
2. Cause & Effect Diagram
3. Histogram
4. Control Charts
5. Scatter Diagrams
6. Graphs
7. Flow Chart

8. All this tools are important tools used widely at
manufacturing field to monitor the over all
operation and to improve the manufacturing
process.
 The modes of defects on production line are
investigated through direct observation on the
production line and statistical tools.

9. What is a Cause and Effect Diagram?.
A graphic tool that helps identify, sort, and
display possible causes of a problem or quality
characteristic.

10. Cause and Effect Diagram
Purpose: Graphical representation of the trail leading to the root
cause of a problem.
Characteristics:
Decide which quality characteristic, outcome or effect you want
to examine (may use Pareto chart).
Backbone –draw straight line.
Ribs – categories.
Medium size bones –secondary causes.
Small bones – root causes.

11. STEPS TO CONSTRUCT
First, clearly identify and define the problem or effect for
which the causes must be identified. Place the problem or effect
at the right or the head of the diagram.
Identify all the broad areas of the problem.
Write in all the detailed possible causes in each of the broad
areas.
Each cause identified should be looked upon for further more
specific causes.
View the diagram and evaluate the main causes.
Set goals and take action on the main causes.

17. APPLICATIONS
 Helps determine root causes.
 Encourages group participation.
 Uses an orderly, easy-to-read format.
 Indicates possible causes of variation.
 Increases process knowledge.
 Identifies areas for collecting data.

18. Flow chart
What Is a Flowchart?
A diagram that uses graphic symbols to depict
the nature and flow of the steps in a process.

19. BENEFITS OF USING FLOWCHARTS
Promote process understanding.
Provide tool for training.
Identify problem areas and improvement
opportunities.

21. HISTOGRAM
Histogram Defined
A histogram is a bar graph that shows frequency data.
Histograms provide the easiest way to evaluate the distribution of
data.

22. Benefits:
 Allows you to understand at a glance the variation that
exists in a process.
 The shape of the histogram will show process behavior.
 The shape and size of the dispersion will help identify
otherwise hidden sources of variation.
 Used to determine the capability of a process.
 Starting point for the improvement process.

23. PARETO CHART
Pareto Principle
Vilfredo Pareto (1848-1923) Italian economist
20% of the population has 80% of the wealth.
Adapted by Joseph Juran. Remember the 80/20
rule states that approximately 80% of the problems
are created by approximately 20% of the causes.

24. PARETO CHARTS
PURPOSE:
Prioritize problems.
HOW IS IT DONE?
Create a preliminary list of
problem classifications.
Tally the occurrences in
each problem classification.
Arrange each classification
in order from highest to
lowest
Construct the bar chart

25. PARETO CHARTS
Benefits:
 Pareto analysis helps
graphically display results
so the significant few
problems emerge from the
general background.
 It tells you what to work on
first.
0
20
40
60
80
100
120
Quantity
Defects 104 42 20 14 10 6 4
Dent Scratch Hole Others Crack Stain Gap

26. Pareto Charts
• Weighted Pareto charts use the quantity of
defects multiplied by their cost to determine
the order.
0
100
200
300
400
500
600
700
800
900
WeightedCost
Weighted cost 800 208 100 80 42 14 6
Gap Dent Hole Crack Scratch Others Stain
Defect Total Cost
Weighted
cost
Gap 4 200 800
Dent 104 2 208
Hole 20 5 100
Crack 10 8 80
Scratch 42 1 42
Others 14 1 14
Stain 6 1 6

28. SCATTER DIAGRAMS
When solving a problem or analyzing a situation one
needs to know the relationship between two variables.
A relationship may or may not exist between two
variables. If a relationship exists, it may be positive or
negative, it may be strong or weak and may be simple or
complex.
 A tool used to study the relationship between two
variables is known as Scatter Diagram.

29. It consists of plotting a series of points representing several
observations on a graph in which one variable is on X-axis and the
other variable in on Y-axis.
The way the points lie scattered in the quadrant gives a good
indication of the relationship between the two variables.

30.  Check sheets are tools for collecting data. They are designed
specific to the type of data to be collected. Check sheets aid
in systematic collection of data.
 Some examples of check sheets are daily maintenance check
sheets, attendance records, production log books, etc.
 Data collected using check sheets needs to be meaningfully
classified.
 Such classification helps gaining a preliminary
understanding of relevance and dispersion of the data so
that further analysis can be planned to obtain a meaningful
output.
CHECK SHEETS

31. Check sheets
Purpose:
–Tool for collecting and organizing measured or counted data.
–Data collected can be used as input data for other quality
tools.
Benefits:
–Collect data in a systematic and organized manner.
–To determine source of problem.
–To facilitate classification of data (stratification).

33. GRAPHS
Graphs of various types are used for pictoral representation of
data. Pictoral representation enables the user or viewer to quickly
grasp the meaning of the data.
Different graphical representation of data are chosen depending on
the purpose of the analysis and preference of the audience. The
different types of graphs used are as given below :

34. Gantt charts illustrate the start and finish dates of the
terminal elements and summary elements of a project.
Terminal elements and summary elements constitute the
work breakdown structure of the project.

35. Line graph
A line graph, also known as a line chart, is a type of chart used to
visualize the value of something over time. For example, a finance
department may plot the change in the amount of cash the company
has on hand over time.

36. Radar Charts are a way of comparing multiple quantitative
variables, Radar Charts are also useful for seeing which
variables are scoring high or low within a dataset, making
them ideal for displaying performance.

37. A band diagram does however try to show the
changes in the band structure from place to place.