Representing Contributory Factors: Fishbone Diagrams and other
formats
ABOUT THIS DOCUMENT
When contributory factors have been identified for a specific problem, it
may be helpful to use a classification framework to classify and group
them. Different methods exist to do this graphically and the fishbone
diagram is a particularly popular method. This document describes the
nature and application of fishbone diagrams and other formats.
A common way of representing contributory factor information: the
fishbone diagram
A common approach is to draw a horizontal arrow on a large sheet of paper or
white board. At the head of the arrow is the problem to be explored (the CDP
or SDP); spines are then added to the arrow in a fishbone arrangement. Each
spine is given a classification heading (from the NPSA Contributory Factors
Classification Framework) which represents the main areas under which you
may want to explore the influencing factors which contributed to the identified
issue or problem (CDP or SDP), see figure 1. It is important to remember that
each fish should explore the contributory factors associated with just one
CDP / SDP.
Organisational and
Strategic
Factors
Task
Factors
Equipment &
Resource
Factors
Working
Condition
Factors
Individual
Factors
Problem or
Issue to be
explored
CDP/SDP
Communication
Factors
Education and
Training
Factors
Team and
Social Factors
Patient
Factors
Diagrams and other formats - Figure 1
It is important to remember that investigators may not find factors for each
heading and that they should not “force” factors merely to have something in
every category. Factors from the strategic / policy heading may be more
relevant for an issue where service delivery is the key problem rather than
care delivery.
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Figure 2 illustrates a Care Delivery Problem from one of the case studies
used in the e-Learning package and shows how the contributory factors can
be categorised according to the framework.
Organisational and
Strategic factors
Tolerance of persistent low
staffing levels.
Equipment and
resource factors
Task factors
Working condition
factors
Individual factors
Patient admitted to ward after
ward round.
No written guidance for who
should see patients presurgery.
Consultant has no fixed time
for ward rounds.
Delay in patient's admission
to ward.
SHO has limited access to
senior medical advice.
Ward busy - 2 patients
requiring 1:1 nursing.
Marking
covered by
sock
SHO inexperienced in
orthopaedics.
Nurse applying sock unsure
of her responsibilities.
SHO unaware of procedure
for marking.
Communication factors
Education and training
factors
Team and social
factors
Patient factors
Example of a Fishbone Diagram - Figure 2
You will also find a template Fishbone to use for this type of analysis in
the Resource Centre.
Again, there may be different ways for presenting data during this stage of the
process and the methodology and template described in the Protocol for
Investigating Clinical Incidents (CRU/ALARM Protocol, Vincent et al 1999)
has also been used widely within the NHS.
Experience has shown that many people find that mapping the contributory
factors via fishbones is a helpful tool that forces them to consider the variety
of issues that can influence performance. However, not everyone likes this
format - therefore it is also perfectly acceptable to consider the contributory
factors either in list form under each of the relevant headings, or in tabular
format. See Figure 3 for a tabular example linked to a timeline. As long as all
the relevant contributory factors have been identified, it does not make a
significant difference which format is used. The important thing is to use the
same classification system in your analyses to ensure consistency and
reliability, rather than to worry about formatting arrangements
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CHRONOLOGY
TIME
Problem/Issue CDPs/SDPs
Contributory
Factors: causal or
influencing*
Main Causal
Factors
(Fundamental
Issues/ Roots)
Recommendations
Figure 3 Chronological Mapping of Problems/issues (CDPs/SDPs) and
associated Contributory Factors
(Taylor-Adams (2002))
You will also find a Template for the Chronological Mapping of Problems
in the Resource Centre.
How to Identify Contributory Factors
The easiest way to identify the contributory factors for each problem identified
when you are a novice is to consider each classification heading in turn and
identify whether or not there were any issues or influences that map under it.
The NPSA classification system can therefore be used in checklist format to
facilitate this process. Brainstorming can help a group identify all the relevant
contributory factors, but if this is being undertaken in a group where there are
sensitivities then the brain-writing technique can easily be applied. Indeed, if
time is tight, this approach can be a distinct advantage as it keeps the group
very focused.
As previously mentioned, both the positive and the negative contributory
factors associated with a Problem/Issue (CDP/SDP) should be identified. We
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normally suggest using different colours, or placing a + next to the positive
factors.
Verification of contributory factors is an important component in the causal
analysis process. It is tempting when investigating a case to use it as an
opportunity to identify all the issues that you know have influenced this case
or similar cases in the past. It is therefore essential that all contributory or
causal factors identified are verified as being significant to the problem/issue
(CDP/SDP) being analysed. Failure to do this will lead to a reduction in the
credibility of the analysis. Failure to authenticate your causal data may lead
the investigation team/RCA participants to focus on an improvement strategy
which does not address the fundamental causes of the incident and therefore
leaves the department and organisation open to the possibility of a similar
incident occurring in the future, Dineen 2002.
Positive Attributes of Causal Analysis using a Contributory Factor
Classification System and Fishbone Diagrams
 it provides a structured and semi-comprehensive system for considering
those influences on performance in an incident
 fishbone diagrams are easily constructed and understood by the novice
investigator
 it allows more reliable improvement strategies to be developed, as they
are based on verified causal information.
Negative Attributes of Causal Analysis using a Contributory Factor
Classification System and Fishbone Diagrams
 contributory classification systems have not been formally validated, the
data which has not been verified may lead to inappropriate improvement
strategies being implemented
 not all investigators feel comfortable with the fishbone diagram format.
*Influencing Factors
An influencing factor is something that influenced the occurrence of, or
outcome of an incident. Generally speaking the incident may have occurred in
any event, and the removal of the influence may not prevent incident
recurrence but will generally improve the safety of the care system
*Causal Factors
A causal factor is something that led directly to an incident. Removal of these
factors will either prevent, or reduce the chances of a similar type of incident
from happening in similar circumstances in the future. Causative factors tend
to be more closely related to the incident being analysed.
References
Dineen M., Six Steps to Root Cause Analysis. Consequence. (Oxford,2002,
ISBN 0-9544328-0-0)
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Taylor-Adams S.E., (2002) Long Version of the CRU/ALARM Protocol. (In
Press, 2002)
Vincent, C., Taylor-Adams, S.E., Stanhope, N. (1998). Framework for analysis
risk and safety in clinical medicine, (British Medical Journal, 1998) pp.316,
1154-7.
Vincent C.A, Adams S, Hewett D, Chapman J et al,. A Protocol for the
Investigation and Analysis of Clinical Incidents. Clinical Risk Unit in
association with the Association of Litigation and Risk Managers (Royal
Society of Medicine Press Ltd, 1999)
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