Page 36 - Safety Risk Management for Medical Devices

CHAPTER 4

Understanding Risk

Abstract
The word “risk” derives from the early Italian risicare, which means “to dare.” The modern concept
of risk and the associated mathematics of probability and statistics were driven first by interest in
gambling. In the 17th century Blaise Pascal, a French mathematician was one of the first to address
the puzzle of probability of the outcomes of a game of chance. There are many types of risk. This
book is focused on safety risks, and contributors to risk. A major contributor to risk is the human,
be it the designer, builder, maintainer, or the user of the System. Assuming good intention, the
main cause of human influence on risk is inconsistency between reality, and the mental model of
reality that the human holds.
Keywords: Risk; contributors to risk; risk perception; mental models

The word “risk” derives from the early Italian risicare, which means “to dare” [10].
The modern concept of risk and the associated mathematics of probability and statis-
tics were driven first by interest in gambling. In the 17th century Blaise Pascal, a
French mathematician was one of the first to address the puzzle of probability of the
outcomes of a game of chance. Pascal turned to Pierre de Fermat and together they
created the theory of probability [10]. This meant that for the first-time people could
make decisions not based on superstition, but based on numbers. Another interesting
consequence of this discovery was the invention of insurance, which itself promoted
risk-taking in business and advanced international commerce.
Risk answers the question: if A happens, what is the probability of B happening. We
employ statistics as a tool to leverage our knowledge of the past to predict the future.
In many cases risk implies choice. That is, with a prediction of the probability
of B, we choose whether to take action A. For example, making an investment while
estimating the probability of a financial gain is a type of risk taking.
Ultimately, risk is about balancing benefit versus cost. Cost in the context of medi-
cal device risk management is injury or damage to health.
It’s important to understand that risk cannot be eliminated—risk is managed. We
cannot build a “safe” device; i.e., a device with zero risk. But we can manage the
risk. Management of risk involves creating boundaries, and then engineering products
such that they do not pose unacceptable levels of risk within those boundaries.
Boundaries include: intended use, intended user, intended use environment, and indi-
cated therapy. According to Ref. [1], in the absence of a specific declaration of

Safety Risk Management for Medical Devices r 2018 Elsevier Ltd.
DOI: https://doi.org/10.1016/B978-0-12-813098-8.00004-0 All rights reserved. 15