The 7 basic quality tools for process improvement

The Seven Basic Tools of Quality (also known as 7 QC Tools) originated in Japan when the country was undergoing major quality revolution and had become a mandatory topic as part of Japanese’s industrial training program. These tools which comprised of simple graphical and statistical techniques were helpful in solving critical quality related issues. These tools were often referred as Seven Basics Tools of Quality because these tools could be implemented by any person with very basic training in statistics and were simple to apply to solve quality-related complex issues.

Quality Glossary Definition: Seven tools of quality

Quality pros have many names for these seven basic tools of quality, first emphasized by Kaoru Ishikawa, a professor of engineering at Tokyo University and the father of "quality circles." Start your quality journey by mastering these tools, and you'll have a name for them too: indispensable.


Cause-and-effect diagram (also called Ishikawa or fishbone diagrams):

Identifies many possible causes for an effect or problem and sorts ideas into useful categories.


Check sheet:

A structured, prepared form for collecting and analyzing data; a generic tool that can be adapted for a wide variety of purposes.


Control chart:

Graph used to study how a process changes over time. Comparing current data to historical control limits leads to conclusions about whether the process variation is consistent (in control) or is unpredictable (out of control, affected by special causes of variation).



The most commonly used graph for showing frequency distributions, or how often each different value in a set of data occurs.


Pareto chart

A bar graph that shows which factors are more significant.


Scatter diagram:

Graphs pairs of numerical data, one variable on each axis, to look for a relationship.



A technique that separates data gathered from a variety of sources so that patterns can be seen (some lists replace stratification with a flowchart or run chart). 

7 QC tools can be applied across any industry starting from product development phase till delivery. 7QC tools even today owns the same popularity and is extensively used in various phases of Six Sigma (DMAIC or DMADV), in continuous improvement process (PDCA cycle) and Lean management (removing wastes from process).


Author: Phan Nguyen

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