The Seven Basic Tools of Quality (English: Seven Basic Tools of Quality), also known as the QC Seven Practices or Elementary Statistical Management Methods or Q7, are seven tools frequently used in quality control. It refers to a set of fixed graphical techniques that can be used to identify problems related to yield and quality in the manufacturing process; they are called basic because they are suitable for people without formal training in statistics.

The Seven Practices of Quality Control originated in Japan after World War II, and were probably introduced by Kaoru Ishikawa, using the analogy of the Seven Weapons of the Musashi-Bo Benkei; the latter in turn was influenced by a series of lectures given to Japanese engineers and scientists in 1950, by Edwards Deming. At the time, companies that trained their workforces in quality control found that the complexity of QC's statistical problems made it difficult for the vast majority of workers, and to make it less difficult, training programs focused on simpler, more convenient QC methods that were sufficient to solve most QC-related problems.

The seven basic tools are contrasted with more advanced statistical techniques such as survey sampling, acceptance sampling, statistical hypothesis testing, experimental design, multivariate analysis, and various methods developed in the field of operations research. The Project Management Institute, in its reference guide to the Project Management Body of Knowledge, refers to these seven basic techniques as a set of conventional tools for planning or controlling the quality of a project.

Expanded Information:

Seven Techniques

1, Fishbone Diagrams (Ishikawa Diagrams, Cause-and-Effect Diagrams, and Characterization Diagrams): To identify the root causes of a problem and its root causes.

2, control chart: the sample mean as the center, three standard deviations above and below the upper and lower limits of control (6 sigma), must pay attention to seven consecutive points fall above or below the average value (Rule of 7) of the rules.

3, histogram: a statistical presentation of the distribution of the middle tendency and the shape of the distribution, regardless of the effect of time.

4, checklist (inventory list): data collection, the number of statistics and then presented in Plato.

5, Plato: the frequency of occurrence of the cumulative order of presentation, mostly applied to 80/20.

6, scatter plot (correlation chart): present the degree of correlation between the two variables each other (positive correlation, negative correlation and zero correlation)

7, stratification: the data will be categorized to find out the trend or characteristics. (The concept can be referred to the statistical concept of stratified sampling)

Baidu Encyclopedia-Quality Control Seven Practices