A type of Root cause analysis
Created by Kaoru Ishikawa - a
Japanese engineering professor
in the 1960s.
Sometimes referred to as
fishbone diagrams, cause-and-
effect diagrams, or Fishikawa

Ishikawa diagram, which depicts the causes of an
event, is frequently used in manufacturing and product
development to define the various steps in a process,
highlight potential trouble spots for quality control, and
identify the resources needed at particular points.

The diagram is shaped
like a fish skeleton, with
the "ribs" representing
the possible contributing
causes of events and the
"head" indicating the
problem or the outcome
of those events.
HEAD
RIBS

The ribs are categorized into
six main factors: the “4Ms, a P
and an E” or measurement,
machines, methods, materials,
people, and environment.
However, you may pick any
factors you want to be the
main factors. And as we can
see in the example each of
these main factors is then
divided into detailed causes for
the specific effect.