Introduction to Health and Safety at Work

4.4 
Human factors and their infl uence 
on safety performance
4.4.1 Human 
factors
Over the years, there have been several studies under-
taken to examine the link between various accident 
types, graded in terms of their severity, and near misses. 
One of the most interesting was conducted in the USA by 
H W Heinrich in 1950. He looked at over 300 accidents/
incidents and produced the ratios illustrated in Figure 4.2.
This study indicated that for every 10 near misses, 
there will be an accident. While the accuracy of this 
study may be debated and other studies have produced 
different ratios, it is clear that if near misses are continu-
ally ignored, an accident will result. Further, the HSE 
Accident Prevention Unit has suggested that 90% of 
all accidents are due to human error and 70% of all 
accidents could have been avoided by earlier (proactive) 
action by management. It is clear from many research 
projects that the major factors in most accidents are 
human factors.
The HSE has defi ned human factors as, ‘environ-
mental, organizational and job factors, and human and 
individual characteristics which infl uence behaviour at 
work in a way which can affect health and safety’.
In simple terms, the health and safety of people at 
work are infl uenced by:
➤
the 
organization
➤
the 
job
➤
personal 
factors.
These are known as human factors since they each have 
a human involvement. The personal factors which dif-
ferentiate one person from another are only one part of 
those factors – and not always the most important.
Each of these elements will be considered in turn.
4.4.2 The 
organization
The organization is the company or corporate body and 
has the major infl uence on health and safety. It must 
have its own positive health and safety culture and pro-
duce an environment in which it:
➤
manages health and safety throughout the organiza-
tion, including the setting and publication of a health 
Major accident
Minor accident
Near miss (no injury)
1
30
300
Figure 4.2
Heinrich’s accidents/incidents ratios.

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