1. to facilitate the exchange of information about current work on health and social services topics amongst practitioners;
2. to disseminate information about OR studies to doctors, nurses, administrators and other health service workers; and
3. to provide a forum for the discussion of matters of interest to OR scientists and their clients in the health and social services.

1. arranges conferences, meetings and workshops (our efforts are concentrated on four one-day conferences per year: past endeavours include a series of meetings on various health-service OR applications and a workshop that led to the Special Interest Group’s submission to the Royal Commission on the NHS);
2. publishes an occasional register of current OR projects in health and social services;
3. maintains a mailing list of people and organisations interested in the application of OR in health and social services; and
4. supports, as appropriate, liaison with other bodies such as the EURO Working Group OR applied to health Services and the Medical Specialists’ Group of the British Computer Society.

Maximising the Impact of OR-Type Health Studies
A YHORG Regional Society/Health & Social Services SIG meeting
Speakers: Tony Lewins, Matthew Bell, Dave Worthington and Prof Alan Brennan
Date/Time: Monday 24 May 2010
Venue: School for Health and Related Research (ScHARR), Sheffield

• Programme:
  An External OR Consultant’s Perspective
  Tony Lewins, Ernst & Young
  The provision of healthcare is currentlyone of the highest profile and most emotive topics in the media.  Growing demand, coupled with pressure on public funding, is resulting in healthcare providers across the country having to make some tough choices about the future structure and delivery of healthcare services.  This talk presents some of the ways that OR is being used to assist with decision-making and uses some specific examples to describe some of the complexity and difficulties that have to be overcome in order to provide effective decision support and to maximise impact.
  An Economist’s Perspective
  Matthew Bell, Frontier Economics
  Economists and Operational Researchers often find themselves working on similar projects in parallel.  Each knows they could benefit from the other but is uncertain how.  This paper sets out, from the perspective of an economist, some of the issues encountered in the economic modelling of health in order to better understand where operational research might help.  It explores the issues in the context of some specific modelling exercises to draw out where economics and OR together might maximise the impact of research studies.
  Queue Modelling and Healthcare: chalk and cheese or fish and chips
  Dave Worthington, Department of Management Science, Lancaster University
  Healthcare systems are rife with queueing systems, some have visible queues, some have invisible queues, and some need to be managed so that queues rarely or never occur. The literature is rife with queueing models, some mathematically based and some simulation-based but only a small proportion of it is relevant to queue management in healthcare. This presentation is about the challenge of making future queue modelling work of greater relevance to healthcare and contributes to the ongoing debate and joint concern of healthcare managers and researchers that future healthcare modelling research should be designed to have real impacts on the delivery of healthcare.
  An Academic Perspective: Research, Evidence, Clinicians and Decisions
  Prof. Alan Brennan, Director of Health Economics & Decision Science, ScHARR
  ScHARR’s Health Economics & Decision Science group, combines the skills of OR modellers, health economists, statisticians, evidence reviewers, information scientists and a small number of clinical academics. This multi disciplinary team collaborates with researchers and clinicians to contribute to policy and evaluation in many areas including design of cancer screening programmes, evaluation of drugs by NICE, and the potential impact of changing the price of alcohol. This presentation, focussing on example projects, covers how such work is done, the approaches the team has taken to increasing the value of our work to decision makers, and a personal view of some of the context factors and barriers which can affect impact.  

IMA Health 2010
Date/Time: 29-31 March 2010
Venue: London

• Abstract submission deadline extended to 25 January 2010
  We invite researchers in all relevant problem domains and methodologies to submit abstracts of 300-500 words to Amy Marsh at Amy.Marsh@ima.org.uk or online at http://online.ima.org.uk/.
  Case studies and methodological papers are both welcome.
  Authors should indicate whether they wish to make an oral or a poster presentation. Poster presentations are particularly welcome as they stimulate discussion and feedback. We are also planning a special poster presentation session for PhD students to show their work in progress.
  Selected papers presented at the conference (whether orally or as a poster) will be published in the Springer journal Health Care Management Science or the IMA Journal of Management Mathematics. 

Maximising The Impact of OR-Type Health Studies
A YHORG Regional Society/Health & Social Services SIG meeting
Speakers: Tony Lewins, Matthew Bell, Dave Worthington and Prof Alan Brennan
Date/Time: Monday 24 May 2010 from 2 – 5.30pm
Venue: School for Health and Related Research (ScHARR), Sheffield

•  Programme:
  An External OR Consultant’s Perspective, Tony Lewins, Ernst & Young
  An Economist’s Perspective, Matthew Bell, Frontier Economics
  Queue Modelling and Healthcare: chalk and cheese or fish and chips, Dave Worthington, Department of Management Science, Lancaster University
  An Academic Perspective: Research, Evidence, Clinicians and Decisions Prof. Alan Brennan, Director of Health Economics & Decision Science, ScHARR

Joint YHORG/Health SIG Meeting
OR in Health: Looking Back and Looking Forward
Speakers:
Geoff Royston, recently retired Manager, OR Group, DOH, Leeds (slides)
Prof Jeff Griffiths, Cardiff University (slides)
Dr Alejandra Duenas, ScHARR, Sheffield (slides)
Prof Jim Chilcott, ScHARR, Sheffield (slides)
Date/Time: Thursday 26th February 2009. 2 - 5pm
Venue: LR1 and 2, first floor of Regent Court, 30 Regent Street, Sheffield, S1 4DA.

• Programme:
  14.00 Welcome & Overview of ScHARR - Jim Chilcott, Reader in Healthcare Operational Research, ScHARR
  14.15 The next fifty years of operational research in health in the UK (with some lessons from the last fifty) - Dr Geoff Royston, Former Head of Strategic Analysis and Operational Research, Department of Health, England.
  The presentation will take a look at likely future developments in health and care and, drawing some lessons from the past, at the associated challenges for OR to make a major impact in the coming years. It takes a practitioner’s perspective, drawing on around thirty years personal experience in the area, on literature in various shades of white and grey, and on views recently sought from prominent UK health analysts. The aim is to stimulate reflective thinking and promote anticipatory action amongst health OR practitioners of the future!
  15.00 What healthcare problems should we be tackling, and how far have we progressed? - Prof Jeff Griffiths, Cardiff University, Past President, ORS
  The speaker will present data relating to various healthcare scenarios within Europe and North America and will consider the advances, which have been made on the modelling front in England and Wales. A review of the current difficulties facing NHS provision will be included, with particular reference to hospital waiting times. A brief overview of healthcare modelling being undertaken in Wales will be presented.
  6.00 Is multi-criteria decision analysis applicable to public health decision making? - Dr Alejandra Duenas, Sheffield School of Health & Related Research ScHARR
  The speaker will describe how the National Institute for Health and Clinical Excellence’s public health intervention guidance process works. The main purpose will be to discuss how multi-criteria decision analysis can be applied to public health decision making and how it’s incorporation may help develop a framework that can provide new ways of addressing decision problems in public health.
  17.00 YHORG AGM

HEALTH SERVICES SOLUTIONS - THE ROLE OF MODELLING AND SIMULATION
Keynote speakers:Nick Black - HSRN Chair, Prof. of Health Services Research LSHTM
Andrew Dillon - Chief Executive, National Institute of Health and Clinical Excellence
Nigel Edwards - Director of Policy, NHS Confederation, Tom Treasure - Prof. of Cardiothoracic Surgery, Chair of the National Confidential Enquiry into Patient Outcome and Death
Date/Time:WEDNESDAY 23 APRIL 2008 (10am - 4pm)
Venue: WESTMINSTER UNIVERSITY, CENTRAL LONDON

• Dear Colleague,
  We would like to bring to your attention the following one-day event which is being organised by MASHnet (The UK Modelling and Simulation in Healthcare Network) in collaboration with the HSRN (Health Service Research Network) and the NHS Confederation. We would be grateful if you could pass this information on to anyone else who you feel would be interested in attending the day. Summary details and booking form are attached (pdf file).
  Focusing on practical healthcare applications and drawing on real experiences, this one day meeting looks at the role of modelling and simulation to address a wide range of healthcare issues. This event will be of interest to researchers, NHS managers and commercial consultants/developers.  The programme includes sessions focused on some of the following issues:

*       Lean Thinking, its role and limitations
*       Operational models of Care, A&E
*       Scheduling and Capacity management
*       Strategic Healthcare Planning
*       The 18 week target
*       Health Technology Assessment
*       Patient safety and clinical monitoring

• Abstract: This talk will present TreeFit, a powerful and user-friendly decision tree software that has been primarily developed for use by the NHS Information Centre (IC). The IC is using TreeFit to assist in the revision of Healthcare Resource Groups (HRGs). HRGs are standard groupings of clinically similar treatments, which use common levels of healthcare resource. They may be considered as “units of currency” within the health service, allowing for costings across services, and will support the UK Department of Health’s policy of Payment by Results.
  Decision trees are data mining tools which are used to represent rules underlying data. Decision trees are hierarchical, sequential classification structures that recursively partition the set of observations (data). The interest of our research was is to create a tool that resulted in more valuable decision trees by enhancing existing theory. In particular, we are considering issues relating to scalability, hybrid trees and the development of “fuzzy trees”. We will present the latest version of TreeFit which includes the following functionality:
• The ability to handle large data sets.
• The capacity to cope with data that contains several distinct values of categorical data.
• Provision of validation of the tree model.
• Possibility to move data across terminal nodes.
• ription of the nodes path.
• Visualisation of the data present in a training model.
• Support to missing values in the data.
• Following the user to interact with the model, choosing the split variable, split values, grow and prune subtrees.

Speaker’s biography: Paul Harper is Professor of Operational Research at Cardiff University and holds the position of WIMCS (Welsh Institute for Mathematical and Computational Sciences) Research Chair in OR. His research interests include healthcare modelling and he has published widely on modelling topics ranging from health service planning (for example hospital capacity models, workforce redesign and facility location problems) to public health policy (for example strategies for screening breast cancer, diabetes and chlamydia). Professor Harper has worked with a number of healthcare organisations and has received research funding from various sources including EPSRC, NHS Information Centre, ESRC and The Nuffield Foundation. He was awarded the 2006 Goodeve medal by the UK OR Society for his co-authored paper on targeted screening strategies for Chlamydia (deemed the best published paper in the Journal of the Operational Research Society in that year).

ABSTRACT:
This one day conference will focus on the practical application of modelling and simulation in healthcare. Demonstrations and presentations which draw on real experiences which reveal the key issues in implementing modelling tools in health and social service organisations.
The conference will appeal to anyone who is interested or engaged in the use or development of modelling and simulation in the health and social services. It will be of specific interest to health service professionals who wish to explore the use of these methods in their work for example in: The delivery of waiting list targets (eg 18 weeks), bed capacity management, forecasting, contingency management, workforce planning etc. It will also be of great interest to those working in research and commercial organisations who are engaged with responding to these needs.
ATTENDANCE: Places at this event are limited to 75 participants and early booking is advised (previous MASHnet day events have been fully booked in advance). Registration at the conference will be acknowledged by email on receipt of a completed booking form and payment. A booking form is attached below.
INFORMATION: A provisional programme for the conference can be downloaded here. Directions for the event, a final programme, participants listing etc will be distributed to the delegates well in advance of the day. Updated information about the latest programme can be found on the MASHnet website: www.mashnet.org.uk

• Aim and Scope.
  The management of Health and Social Care constitutes an important area for the application of concepts and techniques from the disciplines of mathematics, operational research and statistics. Problems such as management of waiting lists and bed capacity, hospital redesign, workforce planning and scheduling, patient flow modelling, performance management, disease monitoring, and health care technology assessment  have been tackled using quantitative techniques including statistical analysis, stochastic processes, queuing theory, mathematical programming, heuristics, discrete event simulation and system dynamics. The aim of the conference is to bring together health care managers, clinicians, management consultants, and mathematicians, operational researchers, statisticians etc from across the world with a view to exploring recent developments and identifying fruitful avenues for further research. The list of keynote speakers reflects this aim.
• Keynote Speakers.
  Andrew Dillon, Chief Executive, National Institute of Clinical Excellence, UK Nigel Edwards, Director of Policy, NHS Confederation, UK Professor Mike Pidd, Associate Dean, Management School, University of Lancaster, UK Professor Steve Gallivan, Director of the Clinical Operational Research Unit, University College London, UK Professor Nick Barber, Head of Department of Practice and Policy, School of Pharmacy, London, UK Professor Yasar Ozcan, Department of Health Administration, Virginia Commonwealth University, USA Professor Stephen Chick, INSEAD, Fontainebleau, France

• Abstract: Dr Foster Intelligence undertakes research into the drivers and measures of healthcare performance, analyses quality and cost data, and provides benchmarking tools to enable clinicians and managers to identify and address areas of high and low performance. In this presentation, the range of tools used by Dr Foster and the underling techniques used to develop the tools will be demonstrated.
• Speaker’s biography: Dr Simon Jones is Head of Analytical Services at Dr Foster Intelligence. Before joining Dr Foster, Simon was Head of Operational Research and Information Services at Bromley Hospitals NHS Trust. Prior to this, Simon was a senior lecturer in operational research at the School of Mathematics, Kingston University. Simon’s research interests include health economics and computer simulation applied to health care.

• Dr Naomi Price-Lloyd: School of Mathematics, Cardiff University, UK
  “A Comparison of Mortality Rates of MRSA and MSSA in an ICU”
  Staphylococcus aureus is a bacterium that lives harmlessly on the skin of approximately a third of healthy people. However, it can cause disease if it enters the body via cuts, surgical incisions, catheters etc. It is thus a growing problem in hospitals, where it can be easily transferred from person-to-person. Symptoms range from relatively superficial skin/wound infections to pneumonia or blood poisoning which may prove fatal, particularly in intensive care patients who are already seriously ill. Historically, Staphylococcus aureus infections have been treated with antibiotics such as Penicillin, and more recently, Methicillin. However, over-prescription and misuse of antibiotics have led to increasing bacterial resistance. Methicillin resistant Staphylococcus aureus (MRSA) is now endemic in many UK hospitals. It must be treated with alternative antibiotics, such as Vancomycin, which is notoriously expensive. This study investigates the difference in mortality rates of patients with MRSA and the non-resistant strain, Methecillin susceptible Staphylococcus aureus (MSSA), in a large intensive care unit, using case-matching techniques and logistic regression models.
• Prof Steve Gallivan: Clinical Operational Research Unit (Director), University College London, UK
  “An Application of Triangles to Safety Research”
  Many believe that measures which reduce the incidence of ‘no harm’ or ‘minor’ safety incidents also reduce the number of ‘major’ incidents, a view championed by Heinrich who suggested that the ratios of such events are relatively constant. A project is discussed initially aimed at establishing such ratios for medication errors. The speaker was asked to advise on statistics and this resulted in the project taking a radical change of direction. A combination of thought experiment and analysis of empirical data showed the project aims were not feasible, casting considerable doubt on Heinrich’s theory.
• Dr Robert C. Lee: Calgary Health Technology Implementation Unit (Director), University of Calgary, Canada
  “Risk Analysis and Risk Management in Cancer Therapy: It’s not as simple as we first thought..”
  Treating cancer with ionizing radiation (radiation therapy) is complex and subject to rare but potentially severe adverse incidents; resulting in morbidity or mortality to multiple patients, along with subsequent litigation and/or criminal action in some cases. Our objective is to implement a quantitative risk and decision analysis model, along with an incident tracking and learning system, to elucidate risks (i.e. probability and consequences of incidents), to inform evidence based risk management and resource allocation decisions, and to improve quality in radiation therapy. We are working with a team of medical physicists, technical staff, and oncologists, and employing several linked conceptual and modelling approaches to inform decision-making. I will describe the project as a whole; then I will focus on a few specific analyses that have been performed to date.

• Abstract: Examples of geographical distribution and organisation of health services are the location of outpatient departments within a city and the provision of particular services such as cardiac, cleft lip and palate, and dental services, across a region. Important issues in the provision of services include the location of the service centres, service capacities, geographical distribution of patients, and ease of access to the health services. These types of geographical problem fall under the general heading of location-allocation problems. In this talk, we review some of the existing location-allocation literature, with particular attention given to those within the health service domain. The development of a stochastic geographical patient-based simulation model is described with case studies from dental services across London, and the provision of cardiac services across Eastern England. Finally, we discuss some future research directions using mathematical network flow models, and collaboration with hospitals in India, where we are hoping to evaluate options for multi-level health services to serve millions of people over a large geographical region.
• Dr Paul Harper is a lecturer in Operational Research, School of Mathematics, University of Southampton. His research interests include modelling for the early detection, prevention and treatment of diseases/medical conditions and modelling for the management of health services.
• Mrs Honora Smith is a PhD research student in Operational Research at the University of Southampton currently researching the mathematics of network flows and social networks with regards to location of healthcare facilities.

• Recently the EPSRC awarded a three-year grant of £60K for a new research network for modelling and simulation in healthcare entitled 'MaSHnet'. This project, which starts in January 2005, was conceived at an OR Society healthcare simulation workshop some time ago and the application (submitted early in 2004) received input and support from a wide range of people with differing backgrounds in the area.
• Mashnet aims to bring together the three communities of health services, academic research and industry to establish a common framework of communication both within and between these domains in order to promote more successful research and implementation.
• This presentation will build on a recent seminar in London where the principle objectives of Mashnet were explored. Specifically it will look at key areas where the separate communities of the health service, academia and industry can best be served and how communication in general can be enhanced. Participants will be invited to provide feedback and help focus the discussion to provide formative input into the development of Mashnet as a successful resource.
• Dr Martin Pitt currently works as a decision analyst and health modeller for the Peninsula Technology Assessment Group based in the new Peninsula Medical School in Exeter. His research background is in modelling for health technology assessment and in computer simulation to support healthcare management with a special interest in information visualisation in these fields. He has worked in both research and applied areas of healthcare. He also lectures on modelling and animation at the Department of Computer Science at Exeter University.

• Recently the EPSRC awarded a three year grant of £60K to fund 'Mashnet' a new research network for modelling and simulation in healthcare. This project due to start in early 2005 was initiated some time ago at an OR healthcare simulation workshop where participants emphasised the need for such a network to be established. The application, submitted early in 2004, received input and support from a wide range of people with differing backgrounds in the area.
• Specifically Mashnet will aim to bring together the three communities of health services, academic research and industry to establish a common framework of communication both within and between these domains in order to promote more successful research and implementation. This presentation will outline the principle objectives of Mashnet and explore the potential of this new network. Key areas of communication will be highlighted as central to the successful future development of modelling and simulation in healthcare within this context.

• Talk 1: The Hospital Episodes Statistics data warehouse: what can it do?
  By: Sheila Dixon, Head of Output, Hospital Episodes Statistics, Department of Health, UK
• The Hospital Episodes Statistics (HES) database contains records of all admitted patient care in NHS Trusts in England. With over 12 million records per year, the database has information on patients (e.g. age, sex, residence), their pathway through hospital (e.g. elective or emergency, dates in and out) and some clinical data (diagnoses and operations). This provides a resource for a number of central and local purposes, such as defining activity, investigating trends, monitoring performance and managing resources. Traditionally reported at national, Trust or health organisation level, HES is also developing analysis at consultant level. This session will look at what HES comprises, how it can be used and a selection of examples of the analysis it offers.
• Talk 2: Leveraging HES data to support health care modelling: A data warehouse approach
  By: Dr Christos Vasilakis, University of Westminster, UK
• Data warehousing and On-Line Analytical Processing (OLAP) tools have become the standard for analytical applications in the business world as they are characterised by powerful data browsing capabilities. However, developing such information systems in the health care domain poses some interesting challenges. It is due to the particular analytical requirements of health decision makers and the unique characteristics of health care data. This talk gives an introduction to data warehousing and OLAP concepts, and a description of a pertinent prototype application that is built around Hospital Episode Statistics data. The prototype primarily supports the analysis of bed occupancy and patient length of stay data, both seen as critical to the development of decision models of patient flow.

• Health reform is a common theme in many jurisdictions. The reasons for reform are numerous, but commonly it appears that the ageing of the population and escalating costs are drivers of reform.
• A review of the South Australian public health sector recently occurred.
• Some of the findings from this review will be presented.
• Compartmental flow modelling has been applied to the analysis of bed occupancy. Such modelling is useful for strategic decision-making. The potential role of strategic bed modelling in health reform will then be discussed. Examples of how this modelling can be used in relation to issues such as the implications of population change, the influence of weather, system changes and benchmarking will be presented.

• This talk presents the findings of an ongoing research programme that has examined how geography and population distribution affect costs and service delivery in the public service arena. Spanning a range of projects for clients such as the DHSS&PS in Northern Ireland, the County Councils Network and the Countryside Agency, a mature approach known as Simplified Modelling of Spatial Systems (SMOSS) has been developed. This approach has allowed comparisons to be made of travel and scale-related effects in delivering public services between different communities - Local Authorities, Districts, and Health Board Areas and so on.

• There are many conditions that can be detected using antenatal screening tests including Down syndrome, haemoglobinopathy and asymptomatic bacteriuria. There are many options for the ways in which these tests can be applied, so many that evaluation by randomised controlled trials is problematic. Modelling gives an alternative method for evaluation. At first sight, one might expect that such evaluation might be amenable to analysis using decision tree methods however we have opted to use alternative methods, based on elementary probability, which allow a wider range of issues to be examined.

• Time spent in hospital by patients may be described in terms of phases, using terms that have been identified by clinicians, such as: diagnosis, assessment, rehabilitative and long-stay. Phase-type distributions, which describe the time to absorption of a continuous time Markov chain, are therefore appropriate to analyse data on lengths of stay of hospital patients. The phases (or transient states of the Markov chain) can be interpreted in terms of increasing severity of any illnesses being treated. This leads to an identification of short-stay, medium-stay and long-stay patients, with the phase-type distribution interpreted as a mixture of such components. Differential effects of two covariates, age of patient at admission and year of admission, are shown on the different phases of the distribution. Extending this approach we can regard spells in and out of hospital as interacting phase type behaviour, where patients may move from phases in hospital to home and phases at home to hospital; death is an absorbing state for both distributions. We may thus derive probabilities of moving from one phase to another, along with the mean number of days spent in each phase. Again these data were analysed to show differential effects of the two covariates: age of patient at first admission and year of first admission. Such an approach can be extended to included costs where different phases (e.g. short-stay, medium-stay, and long-stay) and different situations (e.g. hospital and home) have differential costs.

• As the UK population ages, it is believed that there will be an unsustainable increase in the demand for, and therefore in the costs of long-term care. Although several studies have been performed to estimate these costs, they do not take into account the impact of survival patterns on long-term costs. First we present an explanatory Markov model in continuous-time for the length of stay of elderly people moving within and between residential home care and nursing home care. A procedure to determine the structure of the model and estimate parameters by maximum likelihood is introduced. This explanatory survival model then forms the basis for the development of a generic model for forecasting the costs of institutional long-term care. The models are applied to forecast the total cost over a given period of time, of maintaining a group of individuals in residential and nursing care, funded by an English local authority. Results reveal interesting differences in survival patterns and costs between the types of care. One of the novelties in this framework is that it translates survival inputs (census data and forecasting horizons) and daily costs of care into total cumulative costs in a manner, which is both user-friendly and meaningful to local authority decision makers.

• Max spoke about the issues of performance measurement and meeting targets in health and social care. He will discuss a number of key areas - including developing a balanced set of measures, meeting targets and delivering user-focused services, and ensuring that targets are introduced in a climate of continuous improvement rather than a blame culture. After the talk there will be an opportunity for questions and also to get participants' views on this controversial topic.
• Max is a senior lecturer in Operational Research and Operations Management at Sheffield Hallam University and author of the book 'Delivering Excellence in Health and Social Care' published recently by Open University Press.

• Health systems can be thought of as fuzzy collections of semi-automomous agents, whose responses often seem arbitrary and whose actions are frequently unexpected. The traditional approach to managing such systems has been through the imposition of control through rules, requirements and regulations; experience, particularly in recent years as the complexity of such systems has increased, has demonstrated how inappropriate such an approach can be. The novel behaviours emergent from interaction and co-evolution in complex social systems offer fresh challenges for health service managers. In this presentation we shall introduce and discuss some novel approaches to the development and evaluation of relationships in health service delivery and management. We shall describe some of our recent work relating to clinical governance and to partnerships in primary care to illustrate ways of managing the dilemmas and paradoxes of health service management, as well as talking more widely about some of the generic issues involved.

• Bayesian belief networks (BBNs) are graphical models which represent potential causal relationships between variables and attach probabilities based on Bayes'> Theorem to assess the likelihood of certain events occurring. The extension of Bayesian belief networks to include continuous variables has been considered by Lauritzen et al. (1989) who introduced Conditional Gaussian (CG) distributions.
• However the CG distributions are not appropriate for modelling data that is skewed in nature. This has inspired the development of the conditional phase-type distribution (C-Ph) which uses Bayesian belief networks to represent the interrelationships between discrete variables in the model and a Coxian phase- type distribution to represent skewed survival distributions. The application considered is the modelling of patient outcomes and duration of stay in hospital using BBNs to represent the causal relationships between patient variables and Coxian phase-type distributions to model the continuous distribution of patient survival in hospital.

• Deterministic models of hospital bed occupancy are valuable to understand the occupancy distribution and the average number of beds required, but cannot show the variability in the number of beds, which is precisely the feature that makes planning the number of beds difficult for hospital administrators.
• Using data from a hospital in Adelaide, Australia, a method is presented to estimate release and conversion rates when the admissions are not constant and the nature of the admission process is analyzed. Putting random admission rates into an occupancy model, however, does not produce as much variability in the total number of patients as in the data; it is also necessary to make the releases and conversions random. The possibility of annual as well as weekly patterns in the admission and release rates and implications for hospital planning are also explored.

• Max was a member of Trent Regional Health Authority's Modernisation Board and is author of the book 'Delivering Excellence in Health and published by Open University Press this autumn

• In this seminar, Gerald Midgley will discuss the methodology of systemic intervention that he has been developing over a number of years. He will focus on key aspects of this methodology, such as the need for critical reflection on ethical and boundary judgements, and the value of mixing methods from a wide variety of sources to ensure that intervention is flexible and responsive to stakeholders’ concerns. 
• The methodology will then be illustrated with a case study of an intervention conducted in Central Manchester in which young people and a variety of agencies developed new ideas to support children missing from home or care. The emphases will be on (i) how systemic intervention directs attention to the need to amplify the voices of marginalised stakeholders (such as, in this case, children); and (ii) the value of mixing a variety of problem structuring methods to promote co-operation and mutual learning in a situation where multi-agency working was highly problematic