7 TOOLS OF QUALITY
TQM places a great responsibility on all workers. If employees are to identify and correct quality problems, they need to understand how to assess quality by using a variety of quality control tools, how to interpret findings, and how to correct problems. The seven tools of quality control are extremely useful in identifying and analyzing quality problems. We normally use only one tool at a time, but often a combination of tools is most helpful. These seven tools are listed below.
1. Cause and Effect Diagram
The cause and effect diagram sometimes known as the “Fishbone” or Ishikawa diagram was developed and named by Professor Kaoru Ishikawa of the University of Tokyo in 1950. It is an excellent tool for organizing and documenting potential causes of problems in all areas and at all levels in the organization.
2. Flow Charts
Flowchart is a schematic diagram of the sequence of steps involved in an operation or process. It provides a visual tool that is easy to use and understand. By seeing the steps involved in an operation or process, everyone develops a clear picture of how the operation works and where problems could arise.
3. Check Lists
Checklist is a list of common defects and the number of observed occurrences of these defects. It is a simple yet effective fact-finding tool that allows the worker to collect specific information regarding the defects observed. Checklist is most common used tool in quality and daily life.
4. Control Charts
Control charts are used to evaluate whether the process is operating within set expectations. A control chart reflects the ongoing control of a process and signals an alarm when the process exceeds the control limits. When the limit moves beyond the control limit, it can signal a problem. Once set up, it is an effective tool for day to day monitoring and management of a process.
5. Scatter Diagram
Scatter diagrams are graphs that show how two variables are related to one another. They are particularly useful in detecting the amount of correlation, or the degree of linear relationship, between two variables.
6. Pareto Analysis
This process is derived from Pareto’s Law, named for the Italian economist “Alfredo Pareto (1848 – 1923). Pareto analysis is a technique used to identify quality problems based on their degree of importance. The logic behind Pareto analysis is that only a few quality problems are important, whereas many others are not critical.
A histogram is a vertical bar graph showing the distribution of data in terms of the frequency of occurrence for specific values of data. We can see from the plot what type of distribution a value displays, such as whether it has a normal distribution and whether the distribution is symmetrical.