Seven Tools of Quality
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).