Biomedical Engineering Reference
In-Depth Information
only one remains. That remaining element or constituent is
labeled the “root cause,” or, sometimes, the “probable root
cause.”
4
It is important to consider the entire set of elements that
are candidates for the root cause. Wald and Shojania point
out that “a credible RCA considers root causes in all
categories before rejecting a factor or category of factors as
non-contributory.”
5
Investigators are sometimes prone to identify an individual
employee as the “responsible party” for a deviation. As the
noted authority on accident investigation, James Reason
explains this tendency, “blaming individuals is emotionally
more satisfying than targeting institutions.”
6
In his analysis of models of human error, Reason
distinguishes between the “person approach” and the
“system approach.” Human error can be error in the here
and now, or it can be error inadvertently incorporated at
some time in the past into human products, such as complex
health care systems, laboratory systems, or manufacturing
systems. Thus Reason distinguishes “active failures”
associating human error with individual persons and “latent
conditions” associating human error within a system.
7
The
latent conditions prove more potent in causing deviations
than do the active failures (Table 2.4).
The RCA process has two main phases. In the fi rst
phase, data must be collected allowing a timeline to be
sketched that includes: (a) that which precedes the event;
(b) the deviation (event) itself; and (c) that which follows
the event.
In the second phase, data are analyzed to allow the causes
of the event to be identifi ed, in terms of both the active
failures and the latent conditions. An example of an active
failure would be an employee who fails to follow an SOP; a
latent condition would be a poorly-written SOP.
