I have mentioned before professor Hollnagel
because he made a new definition or tried to do a new definition
of safety. He's field is the health care field.
But he discovered or he realized that there are many things
regarding safety that can be applied to other fields.
So we can say professor Hollnagel didn't define safety
as the absence of something.
Instead, as you can see in the definition,
he said that safety is a condition where the number of successful outcomes,
here he defines everyday work, is as high as possible.
It is the ability to succeed under changing conditions.
So we are going all the time with variability.
If we continue with this, we can say
that safety is defined by its presence.
Something is successful, there is no harm,
that's safety.
So safety is defined by its presence and that leads to the need
to understand everyday performance.
And with everyday performance, professor Hollnagel meant
to understand how people adapt to different conditions.
And, let's say, think of a plane that is traveling
from point Alfa to point Bravo.
And during the trip they have huge turbulences.
They have to adapt to that.
Many planes suffer that. So the pilots adapt to that.
And, for example, two planes are going to another place,
They have other problems like running out of fuel
because for some reasons they started the trip with low fuel.
Things like that. There, the pilots and the ATM controllers
are going to be adapting to the situations.
And we have things like that in air traffic transport
every single day.
Also, if we go to nuclear sector, we will have a lots of valves leaking,
sometimes pumps will fail, things like that.
And nuclear workers are always aware and ready to change things.
So, that's the everyday performance.
We can say also that if the level of safety increases
that means that the proxy measure should increase.
So under this definition safety can only be improved
by situations where it is present.
This is a little bit different that Safety-I analysis.
We can call Safety I also conventional safety
or traditional safety.
Now, let's compare with the bialmodial mode.
And we can do again the question why things go right.
And here we say that Safety II comes
from the success of performance variability in the everyday work.
That means that it is based on everyday performance
carried out by everybody.
And from here we will have both success and failure.
So things will go right or wrong based on the different outcomes.
Like this. Success or acceptable things and failure, unacceptable things,
are going to be variable.
And we have to try to focus on everyday work trying to see
what things, small things but frequent, are going to help us
to improve in the future.
So we can say that it is based on performance variability.
The foundation of Safety II is that the performance adjustments
are ubiquitous and that performance, therefore, is always variable.
Also this is going to lead to analyze the human contribution.
Humans can do positive adjustments more times than negative ones.
So here it's also important to try to focus
on all these positive outcomes.
The idea is that variability shouldn't however be interpreted negatively.
According to Safety I, we have a lot of variable situations,
but all of them, once again, have negative vocabulary.
Like "performance deviations", "violations" or "non-compliance".
On the contrary, the ability to make performance adjustments
is an essential human contribution to work,
without which only the most trivial activity
would not be possible.
Also, Safety I assumes that the causes are real
and the purpose of an accident investigation is
to trace the developments of that accident backwards,
from the observable outcome to the efficient cause.
In the case of an emergency,
the observed final outcomes are also observable.
That means they are real.
But the same is not always necessarily true
for what brought them about.
What do we mean here?
The outcomes, for instance, may be due to transient phenomena or conditions
that only existed during a given time in space and time.
So it is not always easy to trace them back.
These conditions may, in turn, have emerged
from other transient phenomena.
So the causes are thus reconstructed (or inferred) rather than found.
They may therefore be impossible to eliminate or contain
in the usual manner.
But it may still be possible
to control the conditions that brought them into existence,
provided we understand how work normally is done.
So here we can see a little difference between Safety I,
tracing back everything backwards,
and that Safety II what is going to do is
looking at everyday work and analyze that everyday work.
trying to anticipate and to learn
because Safety II is based on resilience.