Ishikawa’s seven basic tools of quality

Dr. Ishikawa believes that 90% of the problems in the business world can be solved with just these simple tools:

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There are already tools and techniques used in perform quality control, and they come under the heading of Ishikawa’s 7 quality tools:

Flowcharting

A process flow chart is created showing the individual steps of a particular process in order to help analysis

Cause and effect diagrams

These are often called fishbone diagrams and are drawn by defining the problem and then analysing variables that would have been impact on the problem itself:

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Histograms

This takes the form of a vertical bar chart where the vertical axis is calibrated in the number of defects:

Pareto Chart

This is a type of histogram but the vertical bars are reordered in the rank of the defect numbers.  This is also known as the 80/20 rule that states and 80% of the problems come from 20 per cent of the causes.  This allows the control and focus on the most serious  80% of the problems:

Run chart

This charts the time history and patterns of variation:

Control charts

This adds an upper and lower control limit of three standard deviations either side of a horizontal center line.  The resulting time plot shows whether a particular system is in or out of control:

Scatter diagrams

This plots points on a two- variable graph, where the clustering and positioning of these points can show the trend information.  Further, it shows the correlation between the two variables, either negative or positive: