Seven Tools of Quality
Tools that help organizations understand their processes to improve them. Followings are the 7 tools –
- Cause and effect diagram: A tool for analyzing process dispersion. It is also referred to as the “Ishikawa diagram,” because Kaoru Ishikawa developed it, and the “fishbone dia-gram,” because the complete diagram resembles a fish skeleton. The diagram illustrates the main causes and subcauses leading to an effect (symptom).
- Check sheet: A simple data recording device. The check sheet is custom designed by the user, which allows him or her to readily interpret the results.
- Control chart: A chart with upper and lower control limits on which values of some statistical measure for a series of samples or subgroups are plotted. The chart frequently shows a central line to help detect a trend of plotted values toward
either control limit. - Flow-chart: A graphical representation of the steps in a process. Flowcharts are drawn to better understand processes.
- Histogram: A graphic summary of variation in a set of data. The pictorial nature of the histogram lets people see patterns that are difficult to detect in a simple table of numbers.
- Pareto chart: A graphical tool for ranking causes from most significant to least significant. The principle, named after 19th century economist Vilfredo Pareto, suggests most effects come from relatively few causes; that is, 80% of the effects come from 20% of the possible causes.
- Scatter diagram: A graphical technique to analyze the relationship between two variables. Two sets of data are plotted on a graph, with the y-axis being used for the variable to be predicted and the x-axis being used for the variable to make the prediction. The graph will show possible relationships (although two variables might appear to be related, they might not be: those who know most about the variables must make that evaluation).