Engineering and Ethics – Week #6 Lecture1
Risk
and Liability in Engineering
Safety
is always a concern for engineers. This module talks about how engineers need to
deal with issues of safety and risk, especially when they involve possible
liability for harm? An important fact is that;
Engineering necessarily involves risk, and risk changes as technology changes.
One cannot avoid risk simply by remaining with tried and true designs, but new
technologies involve risks that may not be as well understood,
potentially increasing the chance of failure or even introducing a previously
unknown mode of failure.
Safety
and risk obviously are related ideas; engineers work to make their designs
safe. Engineers must try to achieve designs that meet cost constraints so they
will be affordable and must work to design and operate engineered systems in
ways that are acceptably safe, which is to say in ways that do not introduce unacceptable
risks. To determine acceptable levels of safety in engineering systems, we
instead try to identify the risks of harm and find ways to quantify those
risks. When the level of risk is determined to be acceptable, we can conclude
the design in question is acceptably safe. Generally
acceptable levels of safety are codified in the specific design codes for the
product or system in question, and the designing engineer only has to adhere to
accepted practice, but when the proposed design deviates from accepted practice
in some important parameter, it may be that the proposed design may introduce
previously unidentified risks.
In
this lecture, three different approaches to risk and safety are
presented, all of which are important in determining public policy
regarding risk. The issues of risk communication and public policy concerning
risk are then examined. Then difficulties in both
estimating and preventing risk from the engineering perspective are discussed. Finally, some of the legal issues surrounding
risk protecting engineers from undue liability and
different approaches of tort law and criminal law to risk are explained.
The Engineer’s approach to Risk
In
order to assess risk, an engineer must identify the risk and quantify it.
Engineers define risk as the product of the likelihood of an event and the
magnitude of the resulting harm. A relatively slight harm that is highly likely
might then constitute a greater risk than a more serious harm that is far less
likely. When engineers quantify risk in this way, they must observe that the
units of this quantity will depend on the exact harm being
considered, so they must be cautious not to quantitatively compare or
add risk quantities that have different units. Engineers have traditionally
thought of harms in terms of things that can be relatively
easily quantified, namely, as impairments of our physical and economic
well-being or the public health, safety, or welfare. Risk is something that can
be objectively measured—namely, the product of the likelihood and the magnitude
of harm.
Defining Acceptable Risk
The
engineering concept of risk focuses on the factual issues of the probability
and magnitude of harm and contains no implicit evaluation of whether a risk is
morally acceptable. In order to determine whether a risk is acceptable,
engineers and risk experts considering engineering solutions often use a
cost-benefit analysis that is fundamentally a utilitarian approach. The
cost-benefit approach compares the costs, including the quantified costs of the
imposed risks of the engineering actions under consideration, with the benefits
of the actions. Then the engineering solution that maximizes net benefits
(benefits minus costs) consistent with economic and other constraints is typically selected. Given the earlier
definition of risk as the product of the probability and the consequences of
harm, one can state the engineer’s criterion of acceptable risk in the
following way: an acceptable risk is one in which the product of the
probability and magnitude of the harm is equaled or exceeded by the product of
the probability and magnitude of the benefit. Cost-benefit analysis is
systematic, offers a degree of objectivity, and provides a way of comparing
risks and benefits by the use of a common measure—namely, monetary cost.
The Capabilities Approach to Identifying Harm and Benefit
A
capability is the real freedom of individuals to achieve a functioning, and it
refers to the real options he or she has available. Capabilities are
constituent elements of individual well-being. Often, people’s preferences or
choices are used to measure satisfaction. Utilities are assigned to represent a preference function. In
determining a risk, the first step is to identify the important capabilities
that might be damaged by a disaster. Then, to quantify
the ways in which the capabilities might be damaged,
we must find some “indicators” that are correlated with the capabilities. Then,
a summary index is constructed by combining the
information provided by each normalized indicator, creating a hazard index
(HI). Finally, to put the HI into the relevant context, its
value is divided by the population affected by the hazard, creating the hazard
impact index, which measures the hazard impact per person.
Some
of the benefits of using capabilities-based approach in identifying the
societal impact of a hazard are discussed. First,
capabilities capture the adverse effects and opportunities of hazards beyond
the consequences traditionally considered. Second, since capabilities are
constitutive aspects of individual well-being, this approach focuses our
attention on what should be our primary concern in assessing the societal
impact of a hazard. Third, the capabilities-based approach offers a more
accurate way to measure the actual impact of a hazard on individuals’
well-being. Fourth, rather than considering diverse consequences, which
increases the difficulty of quantification, the capabilities-based approach
requires considering a few properly selected capabilities.
Communicating Risk and Public Policy
Engineers
define risk as the product of the magnitude and likelihood of harm and are
sympathetic with the utilitarian way of assessing acceptable risk. The professional
codes require engineers to hold paramount the safety, health, and welfare of
the public, so engineers have an obligation to minimize risk. However, in
determining an acceptable level of risk for engineering works, they are likely
to use, or at least be sympathetic with, the cost-benefit approach. The lay
public comes to issues of risk from a very different approach. Part of the
difference in approach results from the tendency to combine judgments of the
likelihood and acceptability of risk. More important, the lay public considers
free and informed consent and equitable distribution of risk (or appropriate
compensation) to be important in the determination of acceptable risk.
In
light of different perspectives, the following guidelines have been proposes
for engineers in risk communication:
1. Engineers, in communicating risk to the public, should be
aware that the public’s approach to risk is not the same as that of the risk
expert. In particular, “risky” cannot be identified
with a measure of the probability of harm. Thus, engineers should not say
“risk” when they mean “probability of harm.” They should use the two terms
independently.
2. Engineers should be wary of saying, “There is no such thing
as zero risk.” The public often uses “zero risk” to indicate not that something
involves no probability of harm but that it is a familiar risk that requires no
further deliberation.
3. Engineers should be aware that the public does not always
trust experts and believes that experts have sometimes been wrong in the past.
Therefore, engineers, in presenting risks to the public, should be careful to
acknowledge the possible limitations in their position. They should also be
aware that laypeople may rely on their own values in
deciding whether or not to base action on an expert’s prediction of probable
outcomes.
4. Engineers should be aware that government regulators have a
special obligation to protect the public, and that this obligation may require
them to take into account considerations other than a strict cost-benefit
approach. Although public policy should take into account cost-benefit
considerations, it should take into account the special obligations of
government regulators.
5. Professional engineering organizations, such as the professional
societies, have a special obligation to present information regarding
technological risk. They must present information that is as objective as
possible regarding probabilities of harm.
Building Codes
The
local building codes is the best way of reflecting on the public policy which
specify factors of safety and construction steps that are required in the area.
Building codes have the status of law and may not be changed
without public hearings and legislative action. The legislature will often
appoint a committee of experts to propose a new building code or necessary
changes in an existing one.
One
of the more important ways professional engineers show a concern for the general public (and their safety) is in carrying out the
local building code requirements in designing such things as buildings,
elevators, escalators, bridges, walkways, roads, and overpasses. When a
responsible engineer recognizes a violation of a building code in a design and
does not object to it, the engineer bears some responsibility for any injuries
or deaths that result. Similarly, when an engineer learns of a proposed change
in a building code that he or she is convinced creates danger for the public
and does nothing to prevent this change, the engineer
bears some responsibility for any harm done.
Difficulties in determining the cause and likelihood of harm
In
actual practice, estimating risk or risk assessment involves an uncertain
prediction of the probability of harm. Some of the methods of estimating risk are: Limitations in Identifying Failure modes, Limitations
due to Tight Coupling and Complex Interactions and Normalizing Deviance and
Self-Deception.
Engineer’s Liability for Risk
Risk
is difficult to estimate and that engineers are often tempted to allow anomalies
to accumulate without taking remedial action, and even to expand the scope of
acceptable risk to accommodate them. We have also seen that there are different
and sometimes incompatible approaches to the definition of acceptable risk as
exhibited by risk experts, laypeople, and government regulators.
Another
issue that raises ethical and professional concerns for engineers regards legal
liability for risk. There are at least two issues here. One is that the
standards of proof in tort law and science are different, and this produces an
interesting ethical conflict. Another issue is that in protecting the public
from unnecessary risk, engineers may themselves incur legal liabilities. Let us
consider each of these issues.
The Standards of Tort Law
Litigation
that seeks redress from harm most commonly appeals to the law of torts, which
deals with injuries to one person caused by another, usually as a result of
fault or negligence of the injuring party. Many of the most famous legal cases
involving claims of harm from technology have been brought
under the law of torts. The major ethical question, however, is whether we
should be more concerned with protecting the rights of plaintiffs who may have been unjustly harmed or with promoting economic
efficiency and protecting defendants against unjust charges of harm. This is
the ethical issue at the heart of the debate.
Protecting Engineers from liability
The
apparent ease with which proximate cause can be established
in tort law may suggest that the courts should impose a more stringent standard
of acceptable risk. But other aspects of the law
afford the public less protection than it deserves. For example, the threat of
legal liability can inhibit engineers from adequately protecting the public
from risk. Engineers in private practice may face especially difficult
considerations regarding liability and risk, and in some cases, they may need
increased protection from liability. If engineers were free to specify safety
measures without being held liable for their neglect
or improper use, they could more easily fulfill one aspect of their
responsibility to protect the safety of the public.
Becoming a responsible engineering regarding risk
The
obligation of engineers is to be ethically responsible with regard to risk. The
first step in the process of becoming ethically responsible about risk is to be
aware of the fact that risk is often difficult to estimate and can be increased
in ways that may be subtle and treacherous. The second step is to be aware that
there are different approaches to the determination of acceptable risk. In
particular, engineers have a strong bias toward quantification in their
approach to risk, which may make them insufficiently sensitive to the concerns
of the lay public and even the government regulators. The third step is to
assume their responsibility, as the experts in technology, to communicate
issues regarding risk to the public, with the full awareness that both the
public and government regulators have a somewhat different agenda with regard
to risk.
Engineers
and risk experts look at risk in a somewhat different way from others in
society. For engineers, risk is the product of the likelihood and magnitude of
harm. An acceptable risk is one in which the product of the probability and magnitude
of the harm is equaled or exceeded by the product of the probability and
magnitude of the benefit, and no other option exists where the product of the
probability and magnitude of the benefit is substantially greater. A risk is
acceptable if the probability is sufficiently small that the adverse effect of
a hazard will fall below a threshold of the minimum level of capabilities
attainment that is acceptable in principle.
Engineers
need to protect themselves from undue liability for risk, but this need
sometimes raises important issues for social policy. The problems engineers
have in protecting themselves from unjust liabilities while protecting the
public from harm are illustrated by the use of trench
boxes. Finally, a principle of acceptable risk provides some guidance in
determining when a risk is within the bounds of moral permissibility.
Summary
Engineers
and risk experts look at risk in a somewhat different way from others in
society. For engineers, risk is the product of the likelihood and magnitude of
harm. An acceptable risk is one in which the product of the probability and
magnitude of the harm is equaled or exceeded by the product of the probability
and magnitude of the benefit, and no other option exists where the product of
the probability and magnitude of the benefit is substantially greater. In
calculating harms and benefits, engineers have traditionally identified harm
with factors that are relatively easily quantified,
such as economic losses and loss of life. The “capabilities” approach attempts
to make these calculations more sophisticated by developing a more adequate way
of measuring the harms and benefits from disasters to overall well-being, which
it defines in terms of the capabilities of people to live the kind of life they
value. A risk is acceptable if the probability is sufficiently small that the
adverse effect of a hazard will fall below a threshold of the minimum level of
capabilities attainment that is acceptable in principle.
Engineers,
and especially professional engineering societies, have an obligation to
contribute to public debate on risk by supplying expert information and by
recognizing that the perspectives in the public debate will comprise more than
the perspective of the risk expert.
Engineers
need to protect themselves from undue liability for risk, but this need
sometimes raises important issues for social policy. One issue is the conflict
between the standards of science and tort law. The standard of proof in tort
law for whether something causes a harm is the preponderance of evidence, but
the standard of evidence in science is much higher. The lower standard of tort
law tends to protect the rights of plaintiffs who may have
been unjustly harmed, and the higher standard of science tends to
protect defendants and perhaps promote economic efficiency. The problems
engineers have in protecting themselves from unjust liabilities while
protecting the public from harm are illustrated by the
use of trench boxes. Finally, a principle of acceptable risk provides some guidance
in determining when a risk is within the bounds of moral permissibility
