The Role of Decision Analysis in Risk Analysis: A Retrospective.

In commemorating the 40th anniversary of Risk Analysis, this article takes a retrospective look at some of the ways in which decision analysis (as a "sibling field") has contributed to the development both of the journal, and of risk analysis as a field. I begin with some early foundational papers from the first decade of the journal's history. I then review a number of papers that have applied decision analysis to risk problems over the years, including applications of related methods such as influence diagrams, multicriteria decision analysis, and risk matrices.

Risk Analysis: Celebrating the Accomplishments and Embracing Ongoing Challenges.

As part of the celebration of the 40th anniversary of the Society for Risk Analysis and Risk Analysis: An International Journal, this essay reviews the 10 most important accomplishments of risk analysis from 1980 to 2010, outlines major accomplishments in three major categories from 2011 to 2019, discusses how editors circulate authors' accomplishments, and proposes 10 major risk-related challenges for 2020-2030. Authors conclude that the next decade will severely test the field of risk analysis.

Measuring and Achieving Equity in Multiperiod Emergency Material Allocation.

Emergency material allocation is an important part of postdisaster emergency logistics that is significant for improving rescue effectiveness and reducing disaster losses. However, the traditional single-period allocation model often causes local surpluses or shortages and high cost, and prevents the system from achieving an equitable or optimal multiperiod allocation. To achieve equitable allocation of emergency materials in the case of serious shortages relative to the demand by victims, this article introduces a multiperiod model for allocation of emergency materials to multiple affected locations (using an exponential utility function to reflect the disutility loss due to material shortfalls), and illustrates the relationship between equity of allocations and the cost of emergency response.

Two Types of Vigilance Are Essential to Effective Hazard Management: Maintaining Both Together Is Difficult.

Flexibility and adaptability are key capabilities for coping with persistent and pervasive uncertainties. The systematic organization of these capabilities is often called "adaptive management"; it is key to effective hazard management and important in risk governance. Vigilance is a requirement for effective adaptation.

Import Security: Assessing the Risks of Imported Food.

We use data on food import violations from the FDA Operational and Administrative System for Import Support (OASIS) to address rising concerns associated with imported food, quantify import risks by product and by country of origin, and explore the usefulness of OASIS data for risk assessment. In particular, we assess whether there are significant trends in violations, whether import violations can be used to quantify risks by country and by product, and how import risks depend on economic factors of the country of origin. The results show that normalizing import violations by volume of imports provides a meaningful indicator of risk.

Quantifying Adversary Capabilities to Inform Defensive Resource Allocation.

We propose a Bayesian Stackelberg game capable of analyzing the joint effects of both attacker intent and capabilities on optimal defensive strategies. The novel feature of our model is the use of contest success functions from economics to capture the extent to which the success of an attack is attributable to the adversary's capability (as well as the level of defensive investment), rather than pure luck. Results of a two-target example suggest that precise assessment of attacker intent may not be necessary if we have poor estimates of attacker capability.

On the treatment of uncertainty and variability in making decisions about risk.

Much attention has been paid to the treatment of dependence and to the characterization of uncertainty and variability (including the issue of dependence among inputs) in performing risk assessments to avoid misleading results. However, with relatively little progress in communicating about the effects and implications of dependence, the effort involved in performing relatively sophisticated risk analyses (e.g.

Risk assessment can be a game-changing information technology--but too often it isn't.

The printing press was a game-changing information technology. Risk assessment could be also. At present, risk assessments are commonly used as one-time decision aids: they provide justification for a particular decision, and afterwards usually sit on a shelf.

Should the model for risk-informed regulation be game theory rather than decision theory?

Risk analysts frequently view the regulation of risks as being largely a matter of decision theory. According to this view, risk analysis methods provide information on the likelihood and severity of various possible outcomes; this information should then be assessed using a decision-theoretic approach (such as cost/benefit analysis) to determine whether the risks are acceptable, and whether additional regulation is warranted. However, this view ignores the fact that in many industries (particularly industries that are technologically sophisticated and employ specialized risk and safety experts), risk analyses may be done by regulated firms, not by the regulator.

Reasons for secrecy and deception in homeland-security resource allocation.

In this article, we explore reasons that a defender might prefer secrecy or deception about her defensive resource allocations, rather than disclosure, in a homeland-security context. Our observations not only summarize and synthesize the results of existing game-theoretic work, but also provide intuitions about promising future research directions.

Securing passenger aircraft from the threat of man-portable air defense systems (MANPADS).

In this article, we develop a model for the expected maximum hit probability of an attack on a commercial aircraft using MANPADS, as a function of the (random) location of the attacker. We also explore the sensitivity of the expected maximum hit probability to the parameters of the model, including both attacker parameters (such as weapon characteristics) and defender parameters (such as the size of the secure region around the airport). We conclude that having a large secure region around an airport offers some protection against MANPADS, and that installing onboard countermeasures reduces the success probability of a MANPADS attack.

Optimal resource allocation for defense of targets based on differing measures of attractiveness.

This article describes the results of applying a rigorous computational model to the problem of the optimal defensive resource allocation among potential terrorist targets. In particular, our study explores how the optimal budget allocation depends on the cost effectiveness of security investments, the defender's valuations of the various targets, and the extent of the defender's uncertainty about the attacker's target valuations. We use expected property damage, expected fatalities, and two metrics of critical infrastructure (airports and bridges) as our measures of target attractiveness.

Choosing what to protect.

We study a strategic model in which a defender must allocate defensive resources to a collection of locations, and an attacker must choose a location to attack. The defender does not know the attacker's preferences, while the attacker observes the defender's resource allocation. The defender's problem gives rise to negative externalities, in the sense that increasing the resources allocated to one location increases the likelihood of an attack at other locations.