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.     

Inference and Decision Making for 21st-Century Drug Development and Approval

ABSTRACT

The cost and time of pharmaceutical drug development continue to grow at rates that many say are unsustainable. These trends have enormous impact on what treatments get to patients, when they get them and how they are used. The statistical framework for supporting decisions in regulated clinical development of new medicines has followed a traditional path of frequentist methodology. Trials using hypothesis tests of “no treatment effect” are done routinely, and the p-value < 0.05 is often the determinant of what constitutes a “successful” trial. Many drugs fail in clinical development, adding to the cost of new medicines, and some evidence points blame at the deficiencies of the frequentist paradigm. An unknown number effective medicines may have been abandoned because trials were declared “unsuccessful” due to a p-value exceeding 0.05. Recently, the Bayesian paradigm has shown utility in the clinical drug development process for its probability-based inference. We argue for a Bayesian approach that employs data from other trials as a “prior” for Phase 3 trials so that synthesized evidence across trials can be utilized to compute probability statements that are valuable for understanding the magnitude of treatment effect. Such a Bayesian paradigm provides a promising framework for improving statistical inference and regulatory decision making.     

Examples of the use of an equivalence theorem in constructing optimum experimental designs for random-effects nonlinear regression models

The problem considered is that of finding an optimum measurement schedule to estimate population parameters in a nonlinear model when the patient effects are random. The paper presents examples of the use of sensitivity functions, derived from the General Equivalence Theorem for D-optimality, in the construction of optimum population designs for such schedules. With independent observations, the theorem applies to the potential inclusion of a single observation. However, in population designs the observations are correlated and the theorem applies to the inclusion of an additional measurement schedule. In one example, three groups of patients of differing size are subject to distinct schedules. Numerical, as opposed to analytical, calculation of the sensitivity function is advocated. The required covariances of the observations are found by simulation.     

Time, Self, and the Curiously Abstract Concept of Agency*

The term "agency" is quite slippery and is used differently depending on the epistemological roots and goals of scholars who employ it. Distressingly, the sociological literature on the concept rarely addresses relevant social psychological research. We take a social behaviorist approach to agency by suggesting that individual temporal orientations are underutilized in conceptualizing this core sociological concept. Different temporal foci—the actor's engaged response to situational circumstances—implicate different forms of agency. This article offers a theoretical model involving four analytical types of agency ("existential,""identity,""pragmatic," and "life course") that are often conflated across treatments of the topic. Each mode of agency overlaps with established social psychological literatures, most notably about the self, enabling scholars to anchor overly abstract treatments of agency within established research literatures.     

Seymour Martin Lipset: The social uses of anomaly

Let me preface my remarks by saying that we are here to honor a living, breathing colleague. My great concern, and in this I am sure that I speak for my colleagues as well, is that any imputation of a postmortem be avoided. Indeed, I would like to believe that Marty will review these various contributions and make his own assessments-critical or approvingly. The fact that he is not present in this conference hall should not deter us from speaking frankly and forthrightly. Marty merits nothing less. What binds us all is the sure knowledge that the work of Lipset speaks to us in personal as well as professional ways. That he has touched so many of us in both the private and public realms is itself a testimonial of the magnitude of his contribution to the field of political sociology. So it is in that spirit of a collégial dialogue that I offer these remarks. Let us hope that a year from now a session of one person can be held, at which S. M. Lipset will provide rebuttals and responses to those of us herein gathered. His most recent work in the field is Behemoth: Main Currents in the History and Theory of Political Sociology. The two major sources for traching the written works of Seymour Lipset are contained in Reexamining Democracy: Essays in Honor of Seymour Martin Lipset, edited by Gary Marx and Martin Diamond. Newberry Park, California: Sage Publishers. 1992, especially pp. 332–355. For work done by Lipset after 1991; as embodied in his later work, see Lipset's essay on “Steady Work: An Academic Memoir,” Annual Review of Socialogy: Greenwich, CT: JAI Press, 1996, pp. 1–27. My reference to works mentioned in the narrative can be found in either of these bibliography sources.     

Quantifying uncertainty in the biospheric carbon flux for England and Wales

Summary.  A crucial issue in the current global warming debate is the effect of vegetation and soils on carbon dioxide (CO₂) concentrations in the atmosphere. Vegetation can extract CO₂ through photosynthesis, but respiration, decay of soil organic matter and disturbance effects such as fire return it to the atmosphere. The balance of these processes is the net carbon flux. To estimate the biospheric carbon flux for England and Wales, we address the statistical problem of inference for the sum of multiple outputs from a complex deterministic computer code whose input parameters are uncertain. The code is a process model which simulates the carbon dynamics of vegetation and soils, including the amount of carbon that is stored as a result of photosynthesis and the amount that is returned to the atmosphere through respiration. The aggregation of outputs corresponding to multiple sites and types of vegetation in a region gives an estimate of the total carbon flux for that region over a period of time. Expert prior opinions are elicited for marginal uncertainty about the relevant input parameters and for correlations of inputs between sites. A Gaussian process model is used to build emulators of the multiple code outputs and Bayesian uncertainty analysis is then used to propagate uncertainty in the input parameters through to uncertainty on the aggregated output. Numerical results are presented for England and Wales in the year 2000. It is estimated that vegetation and soils in England and Wales constituted a net sink of 7.55 Mt C (1 Mt C = 10¹² g of carbon) in 2000, with standard deviation 0.56 Mt C resulting from the sources of uncertainty that are considered.     

Diagnostics for dependence within time series extremes

Summary. The analysis of extreme values within a stationary time series entails various assumptions concerning its long- and short-range dependence. We present a range of new diagnostic tools for assessing whether these assumptions are appropriate and for identifying structure within extreme events. These tools are based on tail characteristics of joint survivor functions but can be implemented by using existing estimation methods for extremes of univariate independent and identically distributed variables. Our diagnostic aids are illustrated through theoretical examples, simulation studies and by application to rainfall and exchange rate data. On the basis of these diagnostics we can explain characteristics that are found in the observed extreme events of these series and also gain insight into the properties of events that are more extreme than those observed.     

LENGTH-BIASING, CHARACTERIZATIONS OF LAWS AND THE MOMENT PROBLEM

A positive random variable X with a finite mean has an induced length-biased law represented by Y, and Y is stochastically larger than X. An independent uniform random contraction of Y, UY, has the same law as X if and only if the latter is exponential. This property is extended to non-uniform contractions and a more general notion of length-biasing. The distributional equality of X and W leads to a functional equation for the moment function of X, which has either Infinitely many solutions or none. When U is constant, X can have a log-normal law, but it can also have laws with the same moment sequence as this log-nod law. The case where U has a certain beta, or generalized beta, law give t3 characterizations of generalized gamma laws, or to products of independent copies of them. This occurs even when these laws are not determined by their moment sequences.     

People and their waste in an emergency context: The case of Monrovia, Liberia

Liberia has gone through civil crisis for over a decade which has resulted in the destruction of infrastructure and disruption of basic services delivery particularly in Monrovia, the capital city. Most of the 1.3 million people living in Monrovia are without adequate environmental sanitation and waste management services which situation poses a serious health risk to the residents. The current waste management service coverage is less than 20% and disposal is by indiscriminate open dumping. In 2003, there were series of outbreaks of cholera epidemics in the city during which time a total of 26,651 cases were reported with many dying.The waste management plan was initiated as an exit strategy of UNICEF following an intervention response programme to assist the Monrovia City Corporation (MCC) whose capacity in this area had been crippled as a result of years of war, through the provision of support in solid waste collection and disposal.The objectives of the plan were to:

(a) Improve waste management services delivery in the city.

(b) Strengthen the ability of the MCC to plan and manage the waste services delivery.

(c) Enhance cooperation of service beneficiaries through comprehensive and effective health education and service promotional campaign.

(d) Enhance revenue generation and community participation through the promotion of private sector and CBOs/NGOs active involvement in the waste management service delivery.

The general methodology adopted for the assignment entailed the following:Desk study and review of existing reports on Water and Environmental Sanitation (WES) in Monrovia and other relevant literature, consultation with stakeholders, site visits and participatory planning which aimed at soliciting the opinions of the various stakeholders involved with the respective components to capture their aspirations and experiences. It also covered collection and analysis of available information and data to facilitate the plan preparation and facilities design.The three-phased strategy (short, medium and long term) covering a period of 10 years (August 2004–December 2014), recommended a combination of technical options for collection based on the pursuit of staged development to allow for the adoption of realistically attainable standards within a framework of continuous and systematic improvements as economic conditions improved and new knowledge gained through practice. The plan sought to blend the capacity within the City Corporation with that of the private sector and NGOs/CBOs to respond to the diverse service demands of the city taking into consideration housing and infrastructural conditions, service costs and cost recovery to ensure sustainability. It also identified sources of financing and allocated financing responsibilities to facilitate effective plan implementation.     

Social identities and political cleavages: the role of political context

Summary. Using a novel method, the paper investigates the influence of social group identities on attitudes and on voting in a variety of political contexts. Examining the major regions of Britain, Canada and the USA, we find considerable national and regional diversity in the nature of social cleavages. For example, social class and race had widely different effects across societies, but within societies their effects on attitudes and on voting were very similar. However, despite that, age and religion had a similar effect on attitudes across societies; the effects on voting varied considerably. The significant within-country differences underline the importance of using region, rather than country, as the unit of analysis. More importantly, these results highlight the role of political context, especially competing cleavages and the structure of party competition, in the establishment of politically relevant social cleavages.