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The Elements of Scientific Advice
Henry Vaux, Jr.
University of California, Berkeley
Introduction
With the passage of time, the substantive and contextual bases in which public policy
must be made grow ever more complex. This is especially true of natural resources and
natural resource policy. The explanation lies with the fact that as populations and
economies have grown, the competitive pressures on natural resources have also grown.
This has led, in turn, to levels of exploitation which either cannot be sustained or can be
sustained only by using management systems which are based upon a clear and
unequivocal understanding of how the underlying natural resource systems behave. The
fact that there are limits to the resiliency of natural resource systems means that the
management of such systems without adequate scientific underpinnings is inherently a
high stakes gamble in which the entire system may be lost or its biological and economic
productivity severely impaired (Houck, 2003).
The success of modern management systems for natural resources is almost always
determined by the adequacy of the scientific understanding of those systems except in
instances in which a policy maker simply rejects the underlying science in the interests of
securing other objectives. To be effective, management strategies must be based upon
and incorporate accurate information about state of the system being managed and about
the way that system will change over time both in the presence and absence of
managerial manipulation. Several different types of scientific information are required.
The first is a description of the current state of the system. In the case of groundwater this
includes information on the depth to the water table and its variation, rates of recharge,
rates of current and prospective extraction, the capacity of the aquifer and the values of
various water quality parameters. The second category of scientific information would
include a description of how the system varies over time and, more specifically, a
characterization of the relationships between the descriptive parameters and all of the
variables that cause those descriptive parameters to change. A third category of
information derives from the second and includes information on how the system will
respond and react to all manner of managerial interventions.
Good managers of natural resource systems are good appliers of science and scientific
information. Thus, the successful manager of groundwater systems has access to the
pertinent scientific information which characterizes the system to be managed and applies
that information in making policy and managerial decisions related to how the
groundwater is managed. A groundwater manager usually cannot be a good or effective
manager if he or she does not have access to the pertinent scientific information. One of
the obligations of scientists and the scientific community is to provide the needed
scientific information to natural resource managers. This can be done either directly,
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through the development of scientific methodology which resource managers can then
employ in developing their own scientific information, or via “coproduction” of
knowledge whereby scientists and managers work together to develop the needed
scientific information. The latter strategy may be particularly attractive since it allows
managers to tailor information development activities to the specifics of the particular
system which they manage and the acquisition of the particular managerial information
which they need.
As the purveyors of critical information that is needed to manage the world’s resources
sustainably to meet multiple objectives, scientists need to be clear regarding what
constitutes adequate scientific advice. What are the elements of such advice and
information? What principles should guide scientists in developing and rendering
scientific advice? The remainder of this paper is devoted to a characterization and
discussion of the elements of good scientific advice, particularly as it is applied to the
management of groundwater systems.
The Elements of Good Scientific Advice: First Principles
Principle # 1: Frequently, scientists compromise their effectiveness and credibility by
failing to distinguish among scientific information, scientific interpretation and policy
value judgments. There is an understandable resentment among policy makers toward
scientists who behave as if their scientific backgrounds make them especially qualified to
make policy value judgments. Policy value judgments are inherently non-scientific and
scientists are no more qualified to make them than anyone else. In addition, scientists
frequently compromise their effectiveness by failing to be clear about what is scientific
fact and what is an interpretation of that fact. The first fundamental principle that should
govern the development of good scientific advice can be stated as follows: It is crucial to
distinguish between fact and what follows logically from fact on the one hand and
interpretation of fact and value judgment on the other. This is not to say that scientists
should be restrained from rendering interpretations of scientific fact and value judgments
about the formulation policy. Rather it is to emphasize that scientists must make clear
when their advice contains elements of interpretation or policy value judgments.
Principle # 2: There are at least three distinct dimensions of scientific advice which can
be offered either independently or in conjunction with each other. These are: 1) existing
scientific knowledge; 2) interpretations of existing scientific knowledge; and 3) methods
for acquiring scientific knowledge. Existing scientific knowledge is comprised of
information that is known with certainty, information that is known probabilistically and
information that is uncertain or unknown1. It is rare that scientific information is known
1
For purposes of this paper the term “risk” is used in situations which are described with a known
set of probabilities and the term “uncertainty” is used to describe situations in which information is
unknown.
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with complete certainty and there are circumstances in which information is unknowable
with scientific certainty. In rendering scientific advice, it is thus important to inform the
decision maker of the relative degree of risk or uncertainty associated with specific pieces
of knowledge so that risk and uncertainty can be accounted for in designing policies and
management strategies. Similarly, interpretations of scientific information rest in part on
what is known with certainty; what is characterized by risk and what is inherently
unknowable and uncertain. Again, in making scientific interpretations, it is important
that the scientists be very clear in describing the extent to which a given interpretation is
based on hard knowledge and the extent to which it is based on probabilistic knowledge
and/or judgments even where they are employed to reduce uncertainty.
There are other circumstances where scientific advice will not consist of scientific
information at all but rather in the characterization and design of processes or methods
for acquiring scientific information either on a one-time or on a continuing basis. Here
again, reliability and accuracy are important characteristics of any system that generates
scientific information. The task of the scientist in these situations is to provide
knowledge not just about methods and processes for acquiring scientific information and
their design but also to characterize ex ante the reliability of the system and the accuracy
of the data which the system produces. Again, there are circumstances where the existing
scientific state of the art does not allow for the gathering of data and knowledge with
complete certainty. A fundamental element for virtually all good scientific advice is that
it characterizes accurately the extent to which the scientific knowledge in question is
known with certainty, is known only probabilistically or is completely unknown
(National Research Council, 1993).
These two principles are the fundamental principles that govern whether scientific advice
is good or not. Advice based on the solidest and most comprehensive bodies of scientific
knowledge will not be good if advisors do not clearly distinguish between facts and
opinions. Similarly, good scientific advice must characterize scientific knowledge
explicitly in terms of what is known with certainty, what is known with some attendant
risk, and what is not known or uncertain. Scientific advice will be severely compromised
and even misleading where these two principles are not followed.
The Elements of Good Scientific Information for Groundwater Management
In an ideal world, a groundwater manager would wish to have comprehensive
information on: 1) the volume of the aquifer; 2) the potential volume of the aquifer; 3) the
depth from surface to water table; 4) the instantaneous rate of recharge; 5) the
instantaneous rate of discharge or extraction; 6) the cost of energy and; 7) water quality
characteristics, including the presence of pathogenic organisms, toxics and other
constituents of concern. This information should be cast according to several important
principles.
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Managing Groundwater Conjunctively
The acquisition of such data requires the generation of knowledge about the aquifer to be
managed as well as the interrelated surface waters, which may play a critical role in
determining what happens to the aquifer. In addition, it will be necessary to know
something about the characteristics of the surrounding vadose zone so as to be prepared
for migrating plumes of materials that could threaten the quality of the groundwater. The
important element here is the interrelatedness of ground and surface water. Historically,
there has been a tendency to separate surface and groundwater with the result that
important interrelationships are ignored and the consequent management strategies are
inadequate (Glennon, 2002). The modern notion of integrated water resources
management emphasizes the importance of managing ground and surface water
conjunctively. If integrated management of water resources is to be successful, the
scientific information on which it is based will also have to be integrated.
Optimizing Scientific Information
The totality of the scientific information that would be useful in managing groundwater is
substantial. While it would be helpful to have access to all such information, it is
important to recognize that information is not costless. Indeed, for most circumstances
the gathering of the information enumerated above on a continuing basis would turn out
to be extremely costly. Consider, for example, the problem of protecting groundwater
from a possible leak in a toxic waste storage pit equipped with a clay liner. As shown in
Table 1, the costs of a monitoring network rise exponentially as the probability of
detection rises. The analysis on which this example is based shows also that the costs of
a monitoring network and the probability of detecting a spill may depend critically on the
shape of the spill or plume profile. The costs associated with uncertainty can be
illustrated further by emphasizing that an optimally designed monitoring grid that will
detect a radial spill with a probability of 0.9 will detect with a probability of only 0.23 if
the spill turns out to be elliptical. These calculations were made assuming that the soil
profile was homogeneous. Most substrates through which water and contaminates
migrate are not homogeneous and this injects further uncertainty and raises still further
the costs of acquiring adequate information (Vaux and Jury, 1985).
Table 1 Number of Sensors Required for Different Probabilities
of Detection with Different Spill Profiles.
Probability # of sensors # of sensors
Radial spill Elliptical spill
0.1 3 27
0.5 21 180
0.9 70 597
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As a general rule, it will not be economical to develop and gather a total or complete set
of scientific information. In economics jargon, the marginal costs of gathering or
developing the last bits of scientific information will outweigh the benefits (one
exception will be instances in which toxic wastes threaten an aquifer and there is no
alternative source of water supply). In offering scientific advice it is important for
scientists and managers alike to be clear regarding the fact that there is an optimal
amount of scientific information (where the net benefits of the information are
maximized) which will be less than a comprehensive set of information in most instances.
Thus, one of the problems of formulating good scientific advice is to determine which
pieces of scientific information are really important and beneficial and which are less
important and less beneficial. Emphasis should always be placed on developing and
communicating the most important and beneficial information first.
Dynamic versus Static Information
Groundwater managers focus on both water quality and water quantity. Competent
groundwater management requires knowledge of how past and current actions will affect
the future qualitative and quantitative conditions of the aquifer in question. The manager
needs to be in a position to anticipate and react to future circumstances. This means that
good scientific information on groundwater will almost always be dynamic or time
dependent. Such information is generated invariably with the aid of groundwater models.
Groundwater models are of varying types, include different sets of parameters, are
accurate over specific ranges of conditions, and vary in the degree of robustness with
respect to different circumstances and parameter values.
Good scientific advice surrounding the adequacy of different groundwater models will
always include information on the appropriateness of the model for the circumstances in
question; the estimates of the degree of accuracy, usually stated in terms of error bars;
and a characterization of both the strengths and weaknesses of the model. In
circumstances in which it is necessary to build new models, data requirements may be
extensive and the data expensive to acquire. Nevertheless, it is important to reiterate that
the quality and accuracy of the model need to be made transparently clear.
Uncertainty and Adaptive Management
In many circumstances good scientific information upon which to base groundwater
management policies and schemes is simply not available. Yet there may be considerable
urgency and need for management in order to protect the resource and to generate
additional supplies of water in circumstances of scarcity. The prescription for such
situations is adaptive management which entails flexible management regimes that can be
altered and adapted as more experience with the system yields more information (Walters
and Holling, 1992). The importance of adaptive management cannot be
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overemphasized.2 Data on groundwater are lacking in many regions of the world even as
the need for groundwater management intensifies. Moreover, projected levels of
population growth suggest that groundwater management will need to become more
pervasive if sufficient quantities are to be available to meet the drinking water and
sanitation demands and grow the additional food needed to support more people.
The challenge here is to design a management regime which serves to protect the aquifer
and generate sustainable levels of extraction in ways that also aid in determining
experimentally the properties of the aquifer and its response to the manipulation of
different management variables. It will rarely be true that the ideal experimental regime
will be the same as a regime designed to accomplish the management objectives for the
aquifer in question, even under uncertainty. The trick, then, is to design a management
regime which balances the need for immediate management intervention and the need for
scientific information. In most such circumstances, the scientist and the groundwater
manager will be required to exercise judgment jointly to design such a system. Here
good scientific advice will consist of knowing how to design an optimal experiment as
well as knowing how to depart from that optimal experiment in ways that will allow
management objectives to be achieved while at the same time ensuring that useful
scientific data will be generated. The need to design groundwater management regimes
which are adaptive and yield useful scientific information relatively quickly represents a
new and important area of endeavor for the groundwater science community (Walters,
1986).
Conclusions
Successful groundwater managers must be masters of many trades. They must be skilled
policy analysts and imaginative devisers of policy. They need excellent communication
and political skills. And they must be good applied scientists. As water demands grow in
response to population and economic growth throughout the world, groundwater
everywhere will need to be managed more intensively if new increments of demand are
to be served. If groundwater managers are to succeed in their ever more complex and
demanding endeavors they will need to have the best possible scientific knowledge and
information.
In developing and communicating this scientific information research scientists must be
mindful of two fundamental principles that govern good scientific advice irrespective of
the kind of science involved. First, it is essential for scientists to be clear always about
the distinction between scientific fact and value judgments. Scientific information
consists of scientific fact and what logically follows from that fact. Interpretations of fact
and value judgments should not be confused with scientific fact and scientists should be
2
However, it is also important to note that there are caveats to adaptive management, especially in the
groundwater context, in which implications of management decisions may not be measurable or observable
for a period of decades due to flow rates.
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clear in labeling interpretation and value judgments for what they are. Second, there is
hardly any certainty about anything. There is always a need for more scientific
information and some phenomena are not completely knowable given the limitations of
the scientific state of the art. In providing scientific information, scientists need to be
clear to distinguish between what is known with certainty, what is known
probabilistically, and what is completely uncertain. The groundwater manager deserves
no less than to be advised when he or she is proceeding in realms where the science is
inadequate or unavailable.
The particular elements of good scientific advice for the specific case of groundwater
management are four in number. First, good groundwater science will acknowledge the
need for integrated water resource management and the science itself will account for and
integrate the relationships between surface and groundwater. Second, it is important to
recognize that scientific information is always costly. Rarely will it be economically
justifiable to insist on complete information. Good scientific advice will focus on the
most significant information and de-emphasize information which is less important or
would be merely nice to have. Third, groundwater is a dynamic resource whose
condition changes with time depending upon environmental and managerial variables.
Good scientific advice should be couched, where possible, in a dynamic framework.
Fourth, and finally, too often there is little or no scientific information available. Here
adaptive management in which the manager learns by doing will require solid scientific
input and a careful balancing between the experimental needs and the objectives of the
management regime.
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References
Glennon, Robert. 2002. Water Follies (Washington, D.C.: Island Press).
Houck, O. 2003. Tales From A Troubled Marriage: Science and Law in Environmental
Policy. Science. Vol. 302. Pp. 1926-1929.
National Research Council. 1993 Groundwater Vulnerability Assessment: Predicting
Relative Contamination Potential Under Conditions of Uncertainty. (Washington,
D.C.: National Academy Press).
National Research Council. 2005. Knowledge-Action Systems for Seasonal to
Interannual Climate Forecasting: Summary of a Workshop. Washington, DC.
National Academies Press.
Vaux, Henry J., Jr. and William A. Jury. 1985. Some Economic Problems of
Groundwater Contamination from Hazardous Waste Disposal Sites. Proceedings
of the Fifteenth Biennial Conference on Groundwater. University of California
Water Resources Center. Riverside, California pp. 103-110.
Walters, C. J. 1986. Adaptive Management of Natural Resources. (New York, N.Y.:
McGraw Hill.)
Walters, C. J. and C. S. Holling. 1990. Large-scale Management Experiments and
Learning By Doing. Ecology. Vol. 71. Pp. 2060-2068.
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Representative terms from entire chapter:
groundwater management
