Table 1
The 7 basic quality tools.
Quality tool Aim
Cause-and-effect diagram
(Ishikawa chart or
fishbone chart)
Identifies many possible causes for an effect or
problem and sorts ideas into useful categories
(machine, method, measure, people, materials,
environment)
Check sheet A structured, prepared form for collecting and
analyzing data that can be adapted for a wide
variety of purposes
Control charts Applied to study how a process changes over
time to identify whether it is under control or
not (if there are special causes affecting the
process outcomes)
Process evolution can also be studied in a
more simplistic way through Linear Graphs
Histogram Shows frequency distributions or how often
each different value occurs in a set of data
Pareto Chart Applied to prioritize problems as it displays
on a bar graph which factors are more
significant.
It is based on the assumption that 80% of the
problems (effects) are caused by 20% of
sources (causes)
Scatter diagram Presents the relationship between two
variables
Stratification It separates data collected from different
sources so that patterns can be seen. Some authors
indicate using the “Flowcharts” with the
stratification to facilitate identifying the
analysis catego