Lawrence D. Phillips

London School of Economics and Political Science | LSE · Department of Management

Randomised controlled trials (RCTs) have long been considered the gold standard of medical evidence. In relation to cannabis based medicinal products (CBMPs), this focus on RCTs has led to very restrictive guidelines in the UK, which are limiting patient access. There is general agreement that RCT evidence in relation to CBPMs is insufficient at pr...

The recent surge in recreational (non-medical) use of nitrous oxide (N2O, also known as ‘laughing gas’) often by inhaling it from balloons, has attracted the attention of some politicians with calls to control its possession under the United Kingdom (UK) Misuse of Drugs Act 1971 (currently selling, but not possession, for recreational use is contro...

Objectives To report the findings of a case-series of 10 children suffering with intractable epilepsies in the UK to determine the feasibility for using whole-plant cannabis medicines to treat seizures in children. Setting This study was conducted retrospectively through collecting clinical data from caretakers and clinicians on study outcome vari...

Background Pharmacological management of chronic neuropathic pain (CNP) still represents a major clinical challenge. Collective harnessing of both the scientific evidence base and clinical experience (of clinicians and patients) can play a key role in informing treatment pathways and contribute to the debate on specific treatments (e.g., cannabinoi...

Background Globally, non-medical heroin use is generating significant public health and social harms, and drug policy about heroin is a controversial field that encompasses many complex issues. Policy responses to illegal heroin markets have varied from militarized eradication of the opium poppy and harsh punishment of users, to more tolerant harm...

Although cannabis-based products for medicinal use are now legal in the UK, it is still challenging for patients to gain access, and only very few National Health Service prescriptions have been written to date. This paper attempts to make sense of why the UK lags behind so many other countries which also have legalised medical cannabis. From consu...

Background: Drug policy, whether for legal or illegal substances, is a controversial field that encompasses many complex issues. Policies can have effects on a myriad of outcomes and stakeholders differ in the outcomes they consider and value, while relevant knowledge on policy effects is dispersed across multiple research disciplines making integ...

Objectives The existing British National Patient Safety Agency (NPSA) safety guideline recommends testing the pH of nasogastric (NG) tube aspirates. Feeding is considered safe if a pH of 5.5 or lower has been observed; otherwise chest X-rays are recommended. Our previous research found that at 5.5, the pH test lacks sensitivity towards oesophageal...

Purpose: The purpose of this study is to draw on the practical experience from the PROTECT BR case studies and make recommendations regarding the application of a number of methodologies and visual representations for benefit-risk assessment. Methods: Eight case studies based on the benefit-risk balance of real medicines were used to test variou...

Background: The PROTECT Benefit-Risk group is dedicated to research in methods for continuous benefit-risk monitoring of medicines, including the presentation of the results, with a particular emphasis on graphical methods. Methods: A comprehensive review was performed to identify visuals used for medical risk and benefit-risk communication. The...

A panel of nine experts applied multi-criteria decision analysis (MCDA) to determine the relative overall harm to users and harms to others of street heroin (injected and smoked) and eleven non-medically used prescription opioids. The experts assessed harm scores for each of the 13 opioids on each of 20 harm criteria, weighted the criteria and expl...

The present paper describes the results of a rating study performed by a group of European Union (EU) drug experts using the multi-criteria decision analysis model for evaluating drug harms. Forty drug experts from throughout the EU scored 20 drugs on 16 harm criteria. The expert group also assessed criteria weights that would apply, on average, ac...

Nasogastric (NG) tubes are commonly used for enteral feeding. Complications of feeding tube misplacement include malnutrition, pulmonary aspiration, and even death. We built a Bayesian network (BN) to analyse the risks associated with available bedside tests to verify tube position. Evidence on test validity (sensitivity and specificity) was retrie...

Assessing the utility of structured approaches to benefit-risk assessment of medicinal products is challenging, in part due to the lack of a gold standard for results and the uncertainty inherent in the data. In place of conducting formal testing, obtaining feedback from users of structured approaches provides insight into their value and limitatio...

Background The need for formal and structured approaches for benefit–risk assessment of medicines is increasing, as is the complexity of the scientific questions addressed before making decisions on the benefit–risk balance of medicines. We systematically collected, appraised and classified available benefit–risk methodologies to facilitate and inf...

Background: An international expert panel convened by the Independent Scientific Committee on Drugs developed a multi-criteria decision analysis model of the relative importance of different types of harm related to the use of nicotine-containing products. Method: The group defined 12 products and 14 harm criteria. Seven criteria represented har...

Experts are perceived to be veridical and to focus only on objective data when evaluating risk. Only a few research studies have attempted to characterize the subjectivity in risk evaluation among experts. Objective. The hypothesis of this study is that expert evaluation of a pharmaceutical drug can be partly explained by dimensions that describe t...

Background: Experts are perceived to be veridical and to focus only on objective data when evaluating risk. Only a few research studies have attempted to characterize the subjectivity in risk evaluation among experts. Objective: The hypothesis of this study is that expert evaluation of a pharmaceutical drug can be partly explained by dimensions...

Background: Shortly after the H1N1 influenza virus reached pandemic status in June 2009, the benefit-risk project team at the European Medicines Agency recognized this presented a research opportunity for testing the usefulness of a decision analysis model in deliberations about approving vaccines soon based on limited data or waiting for more dat...

In order for a medicinal product to get marketing authorization in Europe, it has to demonstrate a positive benefit-risk balance. Although this has been the cornerstone of the evaluation process, there is no standardised methodology that is used in this context. Recognising the need for a structured approach that can enhance the transparency and co...

This chapter presents systems engineering as portfolio analysis carried out with multiple stakeholders who hold different perspectives about the system elements, and where conflicting objectives must be accommodated in deciding what is affordable. A case study of the United Kingdom’s Royal Navy Type 45 destroyer shows how a portfolio approach trade...

This study examines relationship between authoritarianism, conservatism, dogmatism, intolerance of ambiguity and probabilistic thinking. By probabilistic thinking we mean tendency to adopt a probabilistic set, discrimination of uncertainty, and ability to express that uncertainty meaningfully either verbally or as a numerical probability. From orth...

Preliminary research results with drug regulators in several European Agencies show that quantitative models developed with groups of assessors and specialists can integrate scientific data with expert value judgements, thereby extending the capabilities of regulators, and stimulating new insights about key trade-offs. As a result, the rationale fo...

Bayesian belief networks (BBNs) are graphical tools for reasoning with uncertainties (see Chap. 7). They can be used to combine expert knowledge with hard data and making sense of uncertain evidence. The computation of Bayesian inference is complex. In this chapter, we provide a step-to-step guide of how to construct and use Bayesian networks by us...

This review of group dynamic processes covers those main features that are relevant for operations research (OR) practitioners who work with groups. The review brings together disparate literatures reporting experiences with groups, research from empirical studies, observational studies of on-going groups working under stress, and systems for impro...

Proper assessment of the harms caused by the misuse of drugs can inform policy makers in health, policing, and social care. We aimed to apply multicriteria decision analysis (MCDA) modelling to a range of drug harms in the UK. Method Members of the Independent Scientific Committee on Drugs, including two invited specialists, met in a 1-day interac...

Proper assessment of the harms caused by the misuse of drugs can inform policy makers in health, policing, and social care. We aimed to apply multicriteria decision analysis (MCDA) modelling to a range of drug harms in the UK. Members of the Independent Scientific Committee on Drugs, including two invited specialists, met in a 1-day interactive wor...

Bayesian networks (BNs) are graphical tools of reasoning with uncertainties. In recent years, BNs have been increasingly recognized for their capacity to represent probabilistic dependencies explicitly and intuitively, handle incomplete information, and capture expert judgments along with hard data. In this chapter, we examine the underlying logic...

In 1959, LJ Savage attended a statistics seminar held in his honour at the University of London, confronting those present with a radically different approach to reasoning about uncertainty. Britain was well placed to respond to Savage, as very similar ideas had been laid out in Britain a full generation earlier, and in the next few decades, Britis...

In 2003, the UK government set up a broad-based Committee on radioactive waste management (CoRWM) to look at the UK's policy on radioactive waste management with a view to jumpstarting a stalled policy process. The committee's brief was to come up with a set of recommendations that would protect the public and the environment, and be capable of ins...

On the 7th of July 2005, at the peak of morning rush hour, three bombs exploded in short intervals on three London Underground trains. Nearly an hour later,a fourth bomb exploded on a double-deck bus. The bombings killed 52 commuters and the four suicide bombers, injuring over 7001. This paper presents an analysis of the impact of these bombings (7...

Decisions leading to drug approval demand careful attention with respect to balancing benefits and risks. The new benefit-risk assessment model provides reassembling of the pieces of decision-making information using computer software to present a coherent overall picture for decision-makers. The aims of the study were to evaluate content validity...

Managers in both for-profit and not-for-profit organisations continually face the task of allocating resources by balancing costs, benefits and risks and gaining commitment by a wide constituency of stakeholders to those decisions. This task is complex and difficult because many options are present, benefits and risks are rarely expressed as single...

This chapter is based on the writings of Ward Edwards and the recollections of two of his graduate students whom he influenced deeply. Larry Phillips was his student from 1960 to 1966 and Detlof von Winterfeldt was his student from 1970 to 1975. Both continued their interactions with Ward until his death in February 2005. Larry interviewed Ward in...

Bayesian Belief Networks (BBNs) are directed graphs of conditional probabilities that capture the knowledge of experts along with hard data. BBNs aid rational reasoning in situations of uncertainty, and permit inferences to be made about hypotheses of interest. On the basis of the laws of probability, including Bayes's theorem, they provide a clear...

Individual and group-consensus probability distributions were obtained from two independent groups of experts who considered an uncertain quantity relevant to a risk analysis of a proposed nuclear waste facility. A facilitated, structured process helped participants to generate the consensus distribution, and individual distributions were obtained...

This paper concerns the facilitation of working groups whose general aims are to achieve a shared understanding of issues, a sense of common purpose and a mutual commitment to action. We see the main role of the facilitator in such a group as contributing to process and structure, not content. This view is coloured by our assumptions about groups a...

This paper concerns the facilitation of working groups whose general aims are to achieve a shared understanding of issues, a sense of common purpose and a mutual commitment to action. We see the main role of the facilitator in such a group as contributing to process and structure, not content. This view is coloured by our assumptions about groups a...

This paper concerns the facilitation of working groups whose general aims are to achieve a shared understanding of issues, a sense of common purpose and a mutual commitment to action. We see the main role of the facilitator in such a group as contributing to process and structure, not content. This view is coloured by our assumptions about groups a...

Sumario: Decisions involving multiple objectives -- Introduction to probability -- Decision making under uncertainty -- Decision trees and influence diagrams -- Applying simulation to decision problems -- Revising judgements in the light of new information -- The quality of human judgment: laboratory studies -- The quality of human judgment: real-w...

This chapter presents the current status of the decision conference process a way of helping a group of key players to resolve important issues in their organization by working together, under the guidance of an impartial facilitator with the aid of a decision analysis model of participants’ perspectives on the issues developed on-the-spot over a p...

Taking decisions about technological projects whose consequences will be experienced by different groups of people raises a host of difficult problems. Some of these are solved by applying some form of social decision analysis (Howard, 1975), which is the application of decision theory to problems in which there are multiple stakeholders. This pape...

This volume is an outgrowth of a NATO Advanced Research Workshop on "Expert Judgment and Expert Systems," held in Porto, Portugal, August 1986. Support for the Workshop was provided by the NATO Division of Scientific Affairs, the U.S. Army Research Institute, and the U.S. National Science Foundation. The Workshop brought together researchers from t...

A requisite decision model is defined as a model whose form and content are sufficient to solve a particular problem. The model is constructed through an interactive and consultative process between problem owners and specialists (decision analysts). The process of generating the model uses participants' sense of unease about current model results...

Three paradigms are identified as crucial to interpretations of results in most studies of heuristics and biases in probabilistic thinking. The paradigms are criticised as being so limited and inadequate that generalisations from current research on heuristics and biases cannot be justified. In particular, the view of people as ‘intellectual crippl...

Bayesian models for computer-aided underwriting have been developed for a major composite insurance company for two classes of commercial business: motor fleet and fire. The fire model produces a posterior probability distribution over a discretized dimension of risk, defined as the probability of a loss times the severity of the loss, but operatio...

This case study in decision analysis concerns a company that had to decide between continuing to manufacture an old product that might in the near future by banned by the government or introducing an improved but conventional product that would beat the ban but might lose market share to competing products using microchip technology. A decision tre...

With the coming of post-industrial society, organisations will increasingly rely on intellectual technology to aid problem-solving. But those technologies that deal explicitly with uncertainty, such as decision analysis, face special problems hampering their institutionalisation. The main argument of this paper is that success or failure in impleme...

This study reviews research on cultural differences in "probabilistic thinking" and presents some intra- and inter-cultural findings. Strong differences are shown to exist between people raised under Asian and British cultures on measures of this ability. These differences were found to out-weigh any influence of subculture, religion, occupation, a...

Cultural differences in three aspects of "probabilistic thinking" were studied. The study re-presents part of earlier work in Hong Kong and Britain and combines it with the results from a further study in Indonesia and Malaysia. The largest cultural difference was found between Asian and British student groups. The British adopted a more finely dif...

This handbook is intended to provide decision makers and their staffs (current or potential) with an introduction to the basic concepts and operations of decision analysis. Decision analysis is a quantitative method which permits the systematic evaluation of the costs or benefits accruing to courses of action that might be taken in a decision probl...

This paper examines possible cultural influences on probabilistic thinking. By probabilistic thinking we mean the tendency to view the world in terms of uncertainty, the ascribing of different degrees of uncertainty to events, and the ability meaningfully to express that uncertainty either verbally or as a numerical probability. Although one of us...

From the subjectivist point of view (de Finetti, 1937) a probability is a degree of belief in a proposition whose truth has not been ascertained. A probability expresses a purely internal state; there is no “right” or “correct” probability that resides somewhere “in reality” against which it can be compared. However, in many circumstances, it may b...

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As scientists and as technologists we should discard the idea of a ‘true’ or ‘objective’ probability. Instead, we should think of probability judgements as the result of an individual's feelings of uncertainty, translated into a numercial response by internal decision processes. Many factors, both internal and external to the assessor, may influenc...

Bayesian belief networks (BBNs) are graphical tools for reasoning with uncertainties. In BBNs, uncertain events are represented as nodes and their relationships as links, with missing links indicating conditional independence. BBNs perform belief updating when new information becomes available; they can handle incomplete information and capture exp...

Many Decision Analysis interventions can be thought of as helping people to discuss what constitutes value for their organization. One approach to Decision Analysis which takes this view particularly seriously is Decision Conferencing, where valuations assessed locally within particular organizational units may require the assessment of “within-cri...

The extensive research on computer-based medical diagnosis has not had much impact on medical practice because of conflicting results and the apparently high cost of operational systems. The heart of these problems appears to be the unavailability of large amounts of easily retrievable actuarial data needed for the probability estimates about sympt...

A Probabilistic Information Processing System (PIP) uses men and machines in a novel way to perform diagnostic information processing. Men estimate likelihood ratios for each datum and each pair of hypotheses under consideration or a sufficient subset of these pairs. A computer aggregates these estimates by means of Bayes' theorem of probability th...

EXAMINED THE SIMILARITY AMONG VERIDICAL EVENT PROBABILITIES, SUBJECTIVE PROBABILITIES INFERRED FROM SS' ESTIMATES OF THE EVENT PROBABILITIES, AND SUBJECTIVE PROBABILITIES INFERRED FROM CHOICES AMONG BETS INVOLVING THE SAME EVENTS. IN 1 CONDITION, SUBJECTIVE PROBABILITIES WERE BASED ON 2 LEVELS (HIGH AND LOW) OF EXPERIENCE WITH THE RELATIVE FREQUENC...

3 experiments investigated the effects on posterior probability estimates of: (1) prior probabilities, amount of data, and diagnostic impact of the data; (2) payoffs; and (3) response modes. Ss usually behaved conservatively, i.e., the difference between their prior and posterior probability estimates was less than that prescribed by Bayes' theorem...

Subjects were presented with data, described as the simulated output of a computerized radar system, consisting of dots that could fall in any one of twelve sectors. They were told that the process generating the data might be in any one of four mutually exclusive states. Displays showed for each state how likely it was that each dot would fall in...

In most studies of probabilistic inference, subjects have behaved conservatively, i.e., they have revised their probability estimates less than the amount prescribed by Bayes's theorem. This study attempts to shed further light on the conservatism effect by analyzing the process of inductive inference into two components, and determining the effect...