The Rule of Seven

There are many thumb rules and heuristics we follow in different spheres of work and life. The Rule of Seven is one such age old heuristics which works well in many aspects of work. This rule is applicable in business as well as in quality management.

Anything which persists in a pattern may be good or may be bad also. Marketers have used rule of seven in marketing to stress that a customer decides to buy a product only when he or she hears about the product seven or more times persistently. Persistently hearing about the product many times creates a buzz and leads the buyer towards buying the new product. Number seven is more of a heuristics rather than a mathematical rule. 

Rule of seven is also applied in a meaningful way in Quality Management. It is used in conjunction with Control Charts. The Rule of Seven as applied in Quality Management says that “A run of seven or more consecutive points in a control chart, either above the mean, or below the mean, or continuously increasing or decreasing, may indicate the process may be out-of-control”.

Control charts are a very important tool in quality management which are used to study the stability of a process. Below is an example of rule of seven in a control chart.

The above picture depicts Rule of Seven as applied in Quality Management. The points in the control chart are the results or outcomes from the process. Even if all the outcomes are within the specified limits of the control chart, they still convey some potential problem, as the points are creating a trend. Hence a run of seven or more consecutive points within the control chart is a potential indication of problem in in the process and may need investigation. Get enrolled in a Project management professional course online and know more about the rule of seven today with hands-on projects.