The 7 tools of quality control (list below) are used throughout structured problem-solving sequences such as those integral to DMAIC. These tools help practically distill and present complex information in relatively simple, visual formats that assist to track, monitor and control processes, analyze and solve problems, generate ideas, and implement improvements. Concerning the 7 QC Tools, Kaoru Ishikawa (1915 – 1989), the internationally recognized patriarch of quality strategy, was reported to have observed four years before his death that: “… as much as 95 percent of all quality-related problems in the factory can be solved with seven fundamental quantitative tools.” That’s true for office, functional and administrative work units, too.
The tools are:
- Cause-and-Effect Diagrams (or Ishikawaor Fishbone Diagrams): Identify many potential ideas why an effect (problem) is occurring sorting them into practical categories prior to making a prioritized action plan to address.
- Check Sheets (or checklist, tally sheet or defect concentration diagram): An organized format for collecting and analyzing operational and / or functional data flexibly applied for many different circumstances.
- Control Charts: A visual aid depicting whether a process is predictable, capable and / or in control or not, and how it has changed over time.
- Histograms: Commonly employed bar graph technique revealing frequency distributions, that is, how often each different value occurs within a data set.
- Pareto Charts (or Pareto Diagrams): Reveals on a bar graph from left (most significant) to right (least significant) contributing factors. Useful when there are many potential issues and you seek to reveal and concentrate on the most significant.
- Scatter Diagrams (or Shewhart Charts): Graphs pairs of numeric data in order to explore whether a cause and effect relationship between them exists from which to meaningful conclusions.
- Stratification: A technique of ordering information into different groups or layers in order to reveal useful patterns.