Volume 9 – Issue 3 by Magne Myrtveit
Background: Policies assigning low-priority patients treatment delays for care, in order... more Background: Policies assigning low-priority patients treatment delays for care, in order to make room for patients of higher priority arriving later, are common in secondary healthcare services today. Alternatively, each new patient could be granted the first available appointment. We aimed to investigate whether prioritisation can be part of the reason why waiting times for care are often long, and to describe how departments can improve their waiting situation by changing away from prioritisation. Methods: We used patient flow data from 2015 at the Department of Otorhinolaryngology, Haukeland University Hospital, Norway. In Dynaplan Smia, Dynaplan AS, dynamic simulations were used to compare how waiting time, size and shape of the waiting list, and capacity utilisation developed with and without prioritisation. Simulations were started from the actual waiting list at the beginning of 2015, and from an empty waiting list (simulating a new department with no initial patient backlog).Results: From an empty waiting list and with capacity equal to demand, waiting times were built 7 times longer when prioritising than when not. Prioritisation also led to poor resource utilisation and short-lived effects of extra capacity. Departments where prioritisation is causing long waits can improve their situation by temporarily bringing capacity above demand and introducing “first come, first served” instead of prioritisation. Conclusion: A poor appointment allocation policy can build long waiting times, even when capacity is sufficient to meet demand. By bringing waiting times down and going away from prioritisation, the waiting list size and average waiting times at the studied department could be maintained almost 90% below the current level – without requiring permanent change in the capacity/demand ratio.
Papers by Magne Myrtveit
Wirtschaftsinformatik / Angewandte Informatik - WI, 2000
Powersim offers a range of tools for business modelling and simulation. The tools are designed to... more Powersim offers a range of tools for business modelling and simulation. The tools are designed to cope with real-world business situations, addressing complexity as well as dynamic and risk related issues. This article illustrates the use und integrated me thods of the System Dynamics-based tool. A case study shows the profit which could effect an economy if such a tool set comes into operation. The Powersim suite is integrated in SAP's Strategic Enterprise Management (SAP SEM®).
Wirtschaftsinformatik und Angewandte Informatik, Apr 1, 2000
Powersim provides a range of tools for business modelling and simulation. The tools are designed ... more Powersim provides a range of tools for business modelling and simulation. The tools are designed to cope with real-world business situations, addressing complexity as well as dynamic and risk related issues.
1 Abstract The software engineering community ,uses an Object-Oriented Analysis ,and Design (OOAD)
Wirtschaftsinformatik, 2000
Powersim provides a range of tools for business modelling and simulation. The tools are designed ... more Powersim provides a range of tools for business modelling and simulation. The tools are designed to cope with real-world business situations, addressing complexity as well as dynamic and risk related issues.
Proceedings of the 18th International Conference of the System Dynamics Society, 2000
Proceedings of the 16th International Conference of the System Dynamics Society, 1999
In this paper, we attempt to invent a new way to understand risk, measure it, and weigh its conse... more In this paper, we attempt to invent a new way to understand risk, measure it, and weigh its consequences. We attempt to design a rational process for risk-taking; a process that gives the system dynamicist the ability to define what may happen in the future and then to choose among alternatives.
In 1971 Jay Forrester published his book World Dynamics, where he presented a high-level simulati... more In 1971 Jay Forrester published his book World Dynamics, where he presented a high-level simulation model of the socioeconomic environmental world system. The main purpose of the model and the accompanying book was to encourage an open debate about the long-term future on our planet. The World Model was created in a time where pollution and other negative effects of industrialization and economic growth started to become recognized. Forrester made the assumption that life on earth is bounded within certain limits, such as available space and resources. Based on this he concluded that exponential economic growth cannot continue forever; sooner or later one or more limits will be reached. The question, then, is how mankind can manage its own future in ways that can avoid an unpleasant encounter with the limits to growth. The Club of Rome, a non-profit research organization, appointed Dennis Meadows, Donella Meadows and others to elaborate on the work initiated by Forrester. The resulting report, Limits to Growth, became a bestseller almost over night. Large parts of the established economic community reacted with massive criticism towards the limits to growth ideas, and characterized the work as dooms day prophecies with no basis in observed data and established theories. In this essay I describe System Dynamics and econometrics; the scientific home bases of the two sides in the controversy. Based on a theoretical framework developed by Ernan McMullin, I try to categorize the issues that were discussed in the context of the World Model. My findings are that the World Model debate is a mixed controversy, involving different views on facts, theories, principles and values. The controversy has evolved over three decades, and has not ended. The main questions are still relevant and subject to discussion among scientists, politicians, environmentalists, and ordinary people.
The software engineering community uses an Object-Oriented Analysis and Design (OOAD) methodology... more The software engineering community uses an Object-Oriented Analysis and Design (OOAD) methodology to define, design and build software systems. The tools and trade of System Dynamics is heavily dependent upon software to successfully model and solve problems. This paper explores the Object-Oriented concepts of "patterns" and "classes" and how they relate to System Dynamic "models", "components", "molecules", and "archetypes". Specific examples will be discussed with similarities and differences as well as strengths and weaknesses and areas of application. In the Object-Oriented world, design patterns capture generic solutions that have developed and evolved over time and describe them as structures or objects for reuse. These solutions are the subject of untold redesign and re-coding as software engineers have struggled for greater reuse and flexibility in code. Some design patterns can be used "as is" to form solutions or parts of solutions, while others serve as generic templates that can be refined into concrete solutions. The term component (cf. Myrtveit 2000) is used for a model "class" that can serve as a building block when creating model "objects". Components have interfaces defining the variables that carry information between the components and the rest of the model. Design patterns can be used both to implement and to document components. over; this is what makes them experts, . A designer familiar with patterns can apply them to new problems without having to discover them. Patterns have been long recognized in other disciplines as important in crafting complex systems, . Christopher Alexander and his colleagues were probably the first to propose the idea of using a pattern language to architect buildings and cities, . said, "Each pattern describes a problem which occurs over and over again in our environment, and then describes the core of the solution to that problem, in such a way that you can use this solution a million times over, without ever doing it the same way twice", (page x). were talking about buildings and towns; but what he says is true of software object-oriented design, . Regarding patterns, this paper examines the relationships of software object-oriented design and System Dynamics software model design and architectures. Forrester (1990) set the "cornerstone" structures of System Dynamics. suggests that understanding the structure of a subject is essential to understanding the subject. This paper will show that an understanding of the fundamental System Dynamics structures will allow other things, Design Patterns in the Object-Oriented sense, to be related meaningfully. For example, the tools and trade of System Dynamics are heavily dependent upon software to successfully model and solve problems. Since the software engineering community uses an Object-oriented Analysis and Design (OOAD) methodology to define, design and build software systems, the same methodology may apply to System Dynamics. Patterns are fundamental to object-oriented design. A pattern to one person may be a primitive building block to another. For this paper, the point of view of a pattern is as descriptions of communicating objects and classes that are customized to solve a general design problem in a particular context, . To this end, the paper explores the object-oriented concepts of "patterns" and "classes" and how they relate to System Dynamic "models", "components", "molecules", and "archetypes". Specific examples will be discussed with similarities and differences as well as strengths and weaknesses and areas of application.
International Journal of Health Policy and Management, 2019
Background: Policies assigning low-priority patients treatment delays for care, in order to make ... more Background: Policies assigning low-priority patients treatment delays for care, in order to make room for patients of higher priority arriving later, are common in secondary healthcare services today. Alternatively, each new patient could be granted the first available appointment. We aimed to investigate whether prioritisation can be part of the reason why waiting times for care are often long, and to describe how departments can improve their waiting situation by changing away from prioritisation. Methods: We used patient flow data from 2015 at the Department of Otorhinolaryngology, Haukeland University Hospital, Norway. In Dynaplan Smia, Dynaplan AS, dynamic simulations were used to compare how waiting time, size and shape of the waiting list, and capacity utilisation developed with and without prioritisation. Simulations were started from the actual waiting list at the beginning of 2015, and from an empty waiting list (simulating a new department with no initial patient backlog)...
In 1971 Jay Forrester published his book World Dynamics, where he presented a high-level simulati... more In 1971 Jay Forrester published his book World Dynamics, where he presented a high-level simulation model of the socio-economic-environmental world system. The main purpose of the model and the accompanying book was to encourage an open debate about the long-term future on our planet. The World Model was created in a time where pollution and other negative effects of industrialization and economic growth started to become recognized. Forrester made the assumption that life on earth is bounded within certain limits, such as available space and resources. Based on this he concluded that exponential economic growth cannot continue forever; sooner or later one or more limits will be reached. The question, then, is how mankind can manage its own future in ways that can avoid an unpleasant encounter with the limits to growth. The Club of Rome, a non-profit research organization, appointed Dennis Meadows, Donella Meadows and others to elaborate on the work initiated by Forrester. The resulting report, Limits to Growth, became a bestseller almost over night. Large parts of the established economic community reacted with massive criticism towards the limits to growth ideas, and characterized the work as dooms day prophecies with no basis in observed data and established theories. In this essay I describe System Dynamics and econometrics; the scientific home bases of the two sides in the controversy. Based on a theoretical framework developed by Ernan McMullin, I try to categorize the issues that were discussed in the context of the World Model. My findings are that the World Model debate is a mixed controversy, involving different views on facts, theories, principles and values. The controversy has evolved over three decades, and has not ended. The main questions are still relevant and subject to discussion among scientists, politicians, environmentalists, and ordinary people.
The importance of feedback analysis is stressed by SD the community, and the subject is taught at... more The importance of feedback analysis is stressed by SD the community, and the subject is taught at most SD classes. In the practice of business simulations, the identification and study of feedback loops is not so ubiquitous as it deserves. The weak technical support for dynamic analysis of model structures makes it difficult to apply feedback analysis on large models. In addition, the understanding of the dynamic nature of models seems to be quite rudimentary in many areas.
In 1971 Jay Forrester published his book World Dynamics, where he presented a high-level simulati... more In 1971 Jay Forrester published his book World Dynamics, where he presented a high-level simulation model of the socio-economic-environmental world system. The main purpose of the model and the accompanying book was to encourage an open debate about the long-term future on our planet. The World Model was created in a time where pollution and other negative effects of industrialization and economic growth started to become recognized. Forrester made the assumption that life on earth is bounded within certain limits, such as available space and resources. Based on this he concluded that exponential economic growth cannot continue forever; sooner or later one or more limits will be reached. The question, then, is how mankind can manage its own future in ways that can avoid an unpleasant encounter with the limits to growth. The Club of Rome, a non-profit research organization, appointed Dennis Meadows, Donella Meadows and others to elaborate on the work initiated by Forrester. The resul...
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Volume 9 – Issue 3 by Magne Myrtveit
Papers by Magne Myrtveit