Check sheets typically employ a heading that answers the Five Ws: Kaoru Ishikawa identified five uses for check sheets in quality control:[3]: 30 When assessing the probability distribution of a process one can record all process data and then wait to construct a frequency distribution at a later time.
When a process has been identified as a candidate for improvement, it's important to know what types of defects occur in its outputs and their relative frequencies.
This information serves as a guide for investigating and removing the sources of defects, starting with the most frequently occurring.
Additionally, rules for recording the presence of defects of different types when observed for the same process output must be set down.
This chart then determines the order in which the process is to be investigated and sources of variation that lead to defects removed.
When the observation period has concluded, the assessor should reexamine each check sheet and form a composite of the defect locations.
When the observation period has concluded, the combinations of suspect causes with the most symbols should be investigated for the sources of variation that produce the defects of the type noted.
The assessor simply places a check mark next to the "twig" on the branch of the diagram corresponding to the suspected cause when he or she observes a defect.