Seven Basic Tools of Quality for Process Improvement

Quality improvement has become very important in every organization spanning multiple industrial sectors. Maintaining and sustaining the “quality” of the product and services throughout the production process is the main objective of all business enterprises. Customers are willing to pay for high-quality products and services only. Thus, organizations strive to meet their customer’s requirements by improving their business processes and delivering high-quality products and services. These tasks are accomplished by using the 7 quality control tools of quality management.

seven basic tools of quality, 7 tools of quality
7 Quality Control Tools

7 QC Tools of Quality Management

There are seven quality control tools in quality management for process improvement which originated in post-war Japan. Kaoru Ishikawa, a professor of engineering at Tokyo University, introduced these 7 QC Tools of quality management. These tools are basic and easy to use. A simple understanding of these tools helped workers effectively improve the quality of the business process. As a result, Japan became one of the first nations to produce high-quality products that not only fulfilled the requirements of the customers but also helped generate a huge amount of profit for the organizations. The concept of quality improvement was restricted to the manufacturing industries only at that time. Soon, they spread to other industries like pharmaceuticals, healthcare, banking, government, and many more.

When the concept reached the west, automotive and manufacturing industries in America developed it further to match the high-quality production processes of their competitors in Japan. This resulted in the introduction of the concept of Lean and Six Sigma which became the fundamental of quality management. However, the 7 QC Tools are still in practice along with the new process improvement methodologies of Lean, Six Sigma, TQM (Total Quality Management), and Lean Six Sigma. Hence, the seven quality control tools of quality management are believed to be the gold standards for process improvement.

Here are the 7 Basic Quality Control (QC) Tools for Process Improvement in quality management:

  1. Cause-and-effect diagrams (Fishbone or Ishikawa diagram)
  2. Scatter diagrams
  3. Histograms
  4. Control charts
  5. Pareto charts
  6. Check sheets
  7. Stratification

A brief description of these seven quality control tools is given in the following section:

Fishbone or Ishikawa Diagram

Also known as the cause-and-effect diagram was introduced by Kaoru Ishikawa. It helps users to identify the causes or factors of the effect or problem and solve them accordingly. Its resemblance to a fishbone gives its other name. This diagram helps in identifying the root cause of the problem and improving the business process by finding the solution to the effect.

Scatter Diagram

It is also known as a scatter plot and is a statistical quality control tool. Scatter diagram serves the same purpose as the fishbone diagram while establishing a relationship between the causes and the overall effect. These are depicted as variables – X and Y and are used by quality management professionals to analyze the relationship between the two variables. After establishing the relation, professionals can start working toward finding the solution to the problems.


Introduced by Karl Pearson, a histogram is a bar graph that shows the frequency distribution on each bar. It is used to study the areas of improvement that are needed at any given point in time in the production process. Quality professionals use this very often in studying various data like days of the week, physical measurements, the time needed to complete tasks, etc.

Control Chart

This quality control tool is also called Shewhart chart after Walter A. Shewhart. A control chart is a statistical chart used to determine the stability and predictability of the process over time. It helps in reducing process variation by comparing the current data to historical data.

Pareto Chart

This QC Tool named after Vilfredo Pareto is used to determine the biggest contributors to a particular problem. Identifying these factors will help quality management professionals in adjusting the causes and rectifying the problem easily. It is represented in a combination of bar graph and line graph. Pareto chart is based on the 80-20 rule which states that 80% of the problem is caused by 20% of the major factors and the other 20% of the problem is caused by minor factors that amount to 80%.

Check Sheet

This is used to collect quantitative or qualitative data. While collecting quantitative data this quality control tool is referred to as a tally sheet. The purpose of a check sheet is to list important data or information in a table and check their status, this helps in understanding the progress of the production process, find patterns, and solve problems.


This quality control and assurance tool is also called a flowchart or run chart. It divides data into categories and classifies them into groups. Depicting data in a visual representation helps quality professionals derive meaningful information from them and thus, helping them in improving the overall business process.

Knowledge of these seven basic quality control tools will help organizations improve their business processes and increase productivity. The 7 QC Tools are easy enough to understand and having in-depth knowledge in these tools will provide more opportunities for quality management professionals working in various Six Sigma projects.

Importance of 7 QC Tools of Quality Management

As mentioned earlier, the 7 QC Tools can be used in collaboration with other quality management methodologies. For example, in the Define stage of the DMAIC phases of Lean Six Sigma, Flowcharts are used. Fishbone diagrams, Pareto charts, and Control charts are used in the Measure stage. Scatter diagrams, Histograms, and Check sheets are utilized to analyze data in the Analyze stage. Control charts are used in the Improve and Control phases of Six Sigma. Therefore, we can conclude that having the right knowledge and training in understanding the 7 QC Tools of Quality Management can be very beneficial for quality management professionals as well as the organizations they work in.