Basic 7 Tools of Quality

Presentation by:Carla Scardino

The Pennsylvania State University

September 27, 2001

Basic 7 Tools of Quality

HistogramsPareto ChartsCause and Effect DiagramsCheck SheetsScatter DiagramsFlowchartsControl Charts

Kaoru Ishikawa

Ishikawa wanted to change the way people worldwide think about work. He developed the basic seven tools of quality to be used company-wide as an advancement in total quality management.Ishikawa believes that quality improvement is a continuous process.

Kaoru Ishikawa

Ishikawa invented and adapted the basic seven visual tools of quality so that the average person could analyze and interpret data.These tools have been used by thousands of companies and by different levels of managers and employees throughout the world.

Brainstorming Exercise

How can these tools be used in an organization?Think of some specific processes that can be improved as a result of the basic seven tools of quality.

Basic 7 Tools of Quality

HistogramsPareto ChartsCause and Effect DiagramsCheck SheetsScatter DiagramsFlowchartsControl Charts

Histograms

A histogram is a graphical representation of data in a bar chart format.Histograms are also used to observe the “shape” of data.

Histograms

The standard normal distribution

A skewed distribution

Histograms

The width of the histogram bars must be consistent.The classes must be mutually exclusive and all inclusive.The number of the classes is decided by 2k>=n where n is the number of data values and k is the number of classes.

Some rules for developing histograms

Histograms

Histograms can be used to show the relationships of many different collections of data including any process that requires random samples to determine if the process is performing properly.

Pareto Charts

Vilfredo Pareto was the first to develop the 80/20 rule.A Pareto chart was first developed by Joseph Juran who adapted the histogram to be used with the 80/20 rule.Pareto charts identify and prioritize problems that need to be solved.

Pareto Charts

Information must be selected based on types of defects that occur as a result of a process.Data must be collected and categorized.A histogram or frequency chart is constructed showing the number of occurrences.

Rules for developing Pareto Charts

Pareto Charts

Pareto Charts

Pareto charts can be used for a variety of analyses.Some examples of times when Pareto analysis would be useful: identifying and prioritizing complaints from customers, store inventory, and distribution of wealth among countries.

Cause-and-Effect Diagrams

The cause and effect diagram is also called the fishbone diagram or the Ishikawa diagram.It gets its name because the diagram looks like the skeleton of a fish, with the problem being the head and the causes being the “ribs” and the sub-causes being the smaller “bones” stemming from the ribs.

Cause-and-Effect Diagrams

State the problem clearly in the head of the fish.Draw the backbone and ribs.Continue to fill out the diagram asking, “why?” about each cause of the problem.View the diagram and identify core causes.Set goals to address the core causes.

Steps in creating a Fishbone Diagram

Cause-and-Effect Diagrams

example from: http://www.smartdraw.com/resources/examples/business/orgchart10.htm

Cause-and-Effect Diagrams

Cause and effect diagrams are used as an abstract way to depict the causes and effects of the major problems in the process.Some examples of times when fishbone diagrams may be used: causes of delayed flight departures, broken/faulty products, late product delivery

Check Sheets

Check Sheets are data gathering tools that can be used in forming histograms and Pareto charts.Check sheets are a form used to record the frequency of occurrence of certain product or service characteristics related to quality.Check sheets can be either tabular or schematic.

Check Sheets

Identify common defects occurring in the processDraw a tableThe user places check marks on the sheet when a defect is encountered.

Steps in designing a check sheet

Check Sheets

Examples of when check sheets may be helpful: tracking customer complaints at a restaurant; slow production times; faulty/defective products.

Scatter Diagrams

The scatter diagram is used to examine the relationships between variables.Scatter diagrams are used to investigate the possible relationship between two variables that both relate to the same "event." A straight line of best fit (using the least squares method) is often included.

Scatter Diagrams

Scatter Diagrams

Determine the X (independent) and Y (dependent) variablesGather process data relating to the variables identified in step 1Plot the dataObserve the plotted data to see if there is a relationship between the variables.

Steps in setting up a scatter plot

Scatter Diagrams

Examples of when Scatter diagrams can be used to determine if there is a relationship: prevention costs and conformance; overtime hours versus days absent; determining if a particular defect is due to run-size.

FlowchartsSlide 1 of 4

A flowchart is a graphical representation of a process.The first step in many process improvement projects is to create a flowchart.

Flowcharts

Flowcharts

Develop a general process and then fill in the elements of the process.Observe the people doing the process.Determine which steps add value and which do not, to simplify work.Determine whether the work actually needs to be done.

Steps in creating a flowchart

Flowcharts

An example of a process that could use a flowchart would be a restaurant. When the patron enters the restaurant, if there is a table available they are seated. If not, they can wait or sit at the bar and have a drink. When the table becomes available, the patron is seated. After eating, the patron pays for the food and can either leave or sit at the bar.

Control Charts

A control chart is used to determine whether a process will produce a product or service with consistent measurable properties.A control chart has a nominal value, or central line, and an upper and lower control limit.

Control Limits

Control Charts

Take a random sample from the process, measure the quality characteristics, and calculate a variable or attribute measure.If the statistic falls outside the control limits look for assignable cause.Either eliminate or incorporate the cause. Reconstruct the control chart with the new data.

Steps in forming a Control Chart

Control Charts

Examples of when to use control charts: quality inspection and checking for defects in products.

An Exercise in Quality

A real-time histogram activity.

This activity lets you gather data while clicking your mouse every two seconds and creates a histogram while you are clicking.The module will then display the results of the activity in a histogram.

SummaryBasic 7 Tools of Quality

Ishikawa developed the basic seven tools of quality so the average person could analyze and interpret data. These tools have been used in thousands of companies to achieve quality in the organization.Quality improvement is a continuous process that can be made easier by applying these seven tools.

BibliographyFoster Thomas S. Managing Quality An Integrative Approach. New Jersey: Prentice Hall, 2001Krajewski, Lee J., Larry P. Ritzman. Operations Management, Strategy and Analysis. New Jersey: Prentice Hall 2002http://www.skymark.com/resources/leaders/ishikawa.asphttp://quality.enr.state.nc.us/tools/fishbone.htmhttp://www.smartdraw.com/resources/examples/business/orgchart10.htmhttp://www.robertluttman.com/Week5/page11.htmhttp://www.wiley.co.uk/college/busin/icmis/oakman/outline/chap05/slides/symbols.htmhttp://www.skymark.com/resources/tools/management_tools.asp

Basic 7 Tools of QualityPresentation by:

Carla Scardino

The Pennsylvania State UniversitySeptember 27, 2001