The 7QC tools are fundamental instruments used in Japanese manufacturing since the 1960s to improve quality. They are statistical techniques that help analyze production processes, identify problems, control quality fluctuations, and provide solutions. The 7 tools are check sheets, Pareto charts, cause-and-effect diagrams, histograms, scatter diagrams, control charts, and flowcharts. They organize collected data visually and help identify specific issues.

1. QC Tools
The Japanese began applying the thinking developed by Walter Shewhart and W Edward Deming during the 1930s
and 1940s. Japan's progress in continuous improvement led to the expansion of the use of these tools.
Kaoru Ishikawa, the then head of the Japanese Union of Scientists and Engineers (JUSE), thus, decided to expand
the use of these approaches in Japanese manufacturing in the 1960s with the introduction of the seven quality control
(7QC) tools.
7QC tools are fundamental instruments to improve the quality of products. They are used to analyse the production
process, identify major problems, control fluctuations of product quality and provide solutions to avoid future defects.
These tools use statistical techniques and knowledge to accumulate data and analyse them. They help organise the
collected data in a way that is easy to understand. Moreover, by using 7QC tools, specific problems in a process can
be identified.
The first is the check sheet, which shows the history and pattern of variations. This tool is used at the beginning of
the change process to identify the problems and collect data easily.
The team using it can study observed data (a performance measure of a process) for patterns over a specified period
of time. It is also used at the end of the change process to see whether the change has resulted in permanent
improvement.
The Pareto chart is named after Wilfredo Pareto, the Italian economist who determined that wealth is not evenly
distributed. The chart shows the distribution of items and arranges them from the most frequent to the least frequent,
with the final bar being miscellaneous.
The Pareto chart is used to define problems, to set their priority, to illustrate the problems detected and determine
their frequency in the process. It is a graphic picture of the most frequent causes of a particular problem. Most people
use it to determine where to put their initial efforts to get maximum gain.
The cause and effect diagram is also called the "fishbone chart" because of its appearance and the Ishikawa chart
after the man who popularised its use in Japan. It is used to list the cause of particular problems. Lines come off the
core horizontal line to display the main causes; the lines coming off the main causes are the subcauses.
This tool is used to figure out any possible causes of a problem. It allows a team to identify, explore, and graphically
display, in increasing detail, all of the possible causes related to a problem or condition to discover its root cause(s).
The histogram is a bar chart showing a distribution of variables. This tool helps identify the cause of problems in a
process by the shape as well as the width of the distribution. It shows a bar chart of accumulated data and provides
the easiest way to evaluate the distribution of data.
Then there's the scatter diagram, which shows the pattern of relationship between two variables that are thought to
be related.
The closer the points are to the diagonal line, the more closely there is a one-to-one relationship. The scatter diagram
is a graphical tool that plots many data points and shows a pattern of correlation between two variables.
Graphs are among the simplest and best techniques to analyse and display data for easy communication in a visual
format. Data can be depicted graphically using bar graphs, line charts, pie charts and control charts. While the first
three are commonly used, the last is a line chart with control limits.
By mathematically constructing control limits at three standard deviations above and below the average, one can
determine what variation is due to normal ongoing causes (common causes) and what variation is produced by
unique events (special causes).

2. QC Tools
By eliminating the special causes first and then reducing common causes, quality can be improved. Control chart
provides control limits that are three standard deviations above and below average, whether or not our process is in
control.
This tool enables the user to monitor, control and improve process performance over time by studying variation and
its source
7 QC Tools
The use of statistical methods in a systematic manner to identify
root causes of problem.
The 7 QC tools are :-
Data collection Scatter Diagrams
Pareto analysis. Control Charts
Cause and effect diagram Flowcharts
Histograms
Benefits
Essential tools in the continuous Improvement Process.
Provides objective analysis of problems based on facts
and data.
Encourages and enhances teamwork as problems are
addressed through groups.
Able to anticipate potential problems and improve quality
Greater customer satisfaction through superior quality
and services.

3. QC Tools
• Pareto Chart
• Histogram
• Process flow diagram
• Check sheet
• Scatter diagram
• Control chart
• Run Chart
• Cause and Effect Diagram
• Fishbone Diagrams