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This article is part of the [[Systems Science]] Knowledge Area. It presents issues in the comparison and analysis of Systems Approaches by the system science community. Some of these ideas form basic theory and methods that are used in [[Systems Thinking]].
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'''''Lead Author:''''' ''Rick Adcock'', '''''Contributing Authors:''''' ''Scott Jackson, Janet Singer, Duane Hybertson''
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This article is part of the [[Systems Science]] knowledge area (KA). It presents issues in the comparison and analysis of classic {{Term|Systems Approach (glossary)|systems approaches}} developed by the {{Term|Systems Science (glossary)|systems science}} community. Some of these ideas contribute to basic theory and methods that are used in {{Term|Systems Thinking (glossary)|systems thinking}} discussed in the [[Systems Thinking]] KA.
  
 
==What is a Systems Approach?==
 
==What is a Systems Approach?==
  
In Bertalanffy's Introduction to his 1968 GST book, he characterizes a systems approach as:
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In Bertalanffy's introduction to his 1968 book ''[[General System Theory: Foundations, Development, Applications|General System Theory]]'' (GST), he characterizes a systems approach as:
  
<blockquote> ''“A certain objective is given; to find ways and means for its realisation requires the system specialist (or team of specialists) to consider alternative solutions and to choose those promising optimisation at maximum efficiency and minimum cost in a tremendously complex network of interactions”.'' (Bertalanffy, 1968, page 4) </blockquote>
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<blockquote> ''A certain objective is given; to find ways and means for its realization requires the system specialist (or team of specialists) to consider alternative solutions and to choose those promising optimization at maximum efficiency and minimum cost in a tremendously complex network of interactions.'' (Bertalanffy 1968, 4) </blockquote>
  
He goes on to list as possible elements of a systems approach: “classical” systems theory (differential equations); computerization and simulation; compartment theory; set theory; graph theory; net theory; cybernetics; information theory; theory of automata; game theory; decision theory; queuing theory; and models in ordinary language.  
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He goes on to list as possible elements of a systems approach: “classical” systems theory (differential equations), computerization and {{Term|Simulation (glossary)|simulation}}, compartment theory, set theory, graph theory, net theory, {{Term|Cybernetics (glossary)|cybernetics}}, information theory, theory of automata, game theory, decision theory, queuing theory, and {{Term|Model (glossary)|models}} in ordinary language.  
  
This description is similar to what Warren Weaver identified as the methods used successfully by “mixed teams” during WWII on “problems of organized complexity”. However, some conditions that had contributed to success during wartime did not hold after the war, such as a clear focus on well-defined common goals that motivated participants to work across disciplinary boundaries.
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This description is similar to what Warren Weaver identified as the methods used successfully by “mixed teams” during World War II (WWII) on “problems of organized complexity”. However, some conditions that had contributed to success during wartime did not hold after the war, such as a clear focus on well-defined common goals that motivated participants to work across disciplinary {{Term|Boundary (glossary)|boundaries}}.
  
By the early 1970s  there was growing disillusionment with the promise that a Systems Approach would provide easy solutions for all complex problems. There was particular criticism from some, including pioneers of ORMS like Ackoff and Churchman, that reliance on rote mathematical methods to identify optimal solutions among fixed alternatives had become just as inflexible and unimaginative an approach to complex problems as whatever it had replaced. Interest grew in examining and comparing methods and methodologies to better understand what could help ensure the best thinking and learning in terms of systems in systems approaches to practice.
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By the early 1970’s, there was growing disillusionment with the promise that a systems approach would provide easy {{Term|Solution (glossary)|solutions}} for all {{Term|Complex (glossary)|complex}} {{Term|Problem (glossary)|problems}}. There was particular criticism from some, including pioneers of Operations Research and Management Science (ORMS) like Ackoff and Churchman, that reliance on rote mathematical methods to identify optimal solutions among fixed alternatives had become just as inflexible and unimaginative an approach to complex problems as whatever it had replaced. Interest grew in examining and comparing methods and methodologies to better understand what could help ensure the best thinking and learning in terms of systems in systems approaches to practice.
  
 
==Issues in Systems Approaches==
 
==Issues in Systems Approaches==
 
   
 
   
A Systems Approach is strongly associated with [[Systems Thinking (glossary)]] and how it helps to guides systems practice.  In [[What is Systems Thinking?]] the key ideas of considering a system holistically, setting a boundary for a problem/solution of interest and considering the resulting Systems of Interest from outside its boundary are identified (Senge, 2006), (Churchman 1979), Meadows (2010).
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A systems approach is strongly associated with {{Term|Systems Thinking (glossary)|systems thinking}} and how it helps to guide systems practice.  In [[What is Systems Thinking?]] the key ideas of considering a {{Term|System (glossary)|system}} {{Term|Holistic (glossary)|holistically}}, setting a {{Term|Boundary (glossary)|boundary}} for a {{Term|Problem (glossary)|problem}}/{{Term|Solution (glossary)|solution}} of interest, and considering the resulting {{Term|System-of-Interest (glossary)|system-of-interest}} from outside its boundary are identified (Churchman 1979; Senge 2006).
 
    
 
    
A systems approach can view a [[System (glossary)]] as a “holon” – an entity that is itself a “whole system” that interacts with a mosaic of other holons in its wider environment (Hybertson, 2009), while also being made up of interacting parts. We can use this model recursively – each part of the system may be a system in its own right, and can itself be viewed both as an entity as seen from outside, and as a set of interacting parts. This model also applies in upwards recursion, so the original “system of interest” is an interacting part of one or more wider systems.  
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A systems approach can view a system as a “holon” – an entity that is itself a “whole system” that interacts with a mosaic of other holons in its wider environment (Hybertson 2009), while also being made up of interacting parts. We can use this {{Term|Model (glossary)|model}} {{Term|Recursion (glossary)|recursively}} – each part of the system may be a system in its own right, and can itself be viewed both as an entity as seen from outside, and as a set of interacting parts. This model also applies in upwards recursion, so the original “system-of-interest” is an interacting part of one or more wider systems.  
  
This means that an important skill in a systems approach is to identify the “natural holons” in the problem situation and solution systems, and to make the partitioning of responsibilities match the “natural holons”, so as to minimise the coupling between parallel activities when applying a solution. This is the “cohesive/loose coupling” heuristic that has been around for a long time in many design disciplines.
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This means that an important skill in a systems approach is to identify the “natural holons” in the problem situation and solution systems and to make the partitioning of responsibilities match the “natural holons,so as to minimize the coupling between parallel activities when applying a solution. This is the “cohesive/loose coupling” {{Term|Heuristic (glossary)|heuristic}} that has been around for a long time in many design disciplines.
  
Another consequence of the holistic nature of a systems approach is that it considers not only a problem situation and a solution system but also the system created and deployed to apply one to the other. A Systems Approach must consider both the boundary of the system of concern, and the boundary of the system inquiry (or model). Real systems are always open, i.e., they interact with their environment or supersystem(s). On the other hand, real models are always “closed” due to resource constraints — a fixed boundary of consideration must be set. So there is an ongoing negotiation to relate the two in systems practice, and the judgement to do so is greatly helped by an appreciation of the difference between them.  
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Another consequence of the holistic nature of a systems approach is that it considers not only a problem situation and a solution system but also the system created and deployed to apply one to the other. A systems approach must consider both the boundary of the system of concern as well as the boundary of the system inquiry (or model). Real systems are always open, i.e., they interact with their {{Term|Environment (glossary)|environment}} or supersystem(s). On the other hand, real models are always “closed” due to resource {{Term|Constraint (glossary)|constraints}} — a fixed boundary of consideration must be set. Thus, there is an ongoing negotiation to relate the two in systems practice and the judgment to do so is greatly helped by an appreciation of the difference between them.  
  
Thus, a Systems Approach can be characterised by how it considers problems, solutions and the problem resolution process itself.
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Thus, a systems approach can be characterized by how it considers problems, solutions and the problem resolution process itself:
*Consider problems holistically, setting problem boundaries though understanding of natural system relationships and trying to avoid unwanted consequences.   
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* Consider problems holistically, setting problem boundaries though understanding of natural system relationships and trying to avoid unwanted consequences.   
*Create solutions based on sound system principles, in particular creating system structures which reduce organised complexity and unwanted emergent properties.   
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* Create solutions based on sound system principles, in particular creating system structures which reduce organized {{Term|Complexity (glossary)|complexity}} and unwanted {{Term|Emergence (glossary)|emergent}} properties.   
*Use understanding, judgement and models in both problem understanding and solution creation, while understanding the limitations of such views and models.
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* Use understanding, judgment and models in both problem understanding and solution creation, while understanding the limitations of such views and models.
  
 
==Systems Methodologies==
 
==Systems Methodologies==
One topic that has received significant attention in the Systems Science community is the analysis and comparison of methodologies which implement a Systems Approach. A methodology is a body of tools, procedures, and methods applied to a problem situation, ideally derived from a theoretical framework. These describe structured approaches to problem understanding and/or resolution making use of some of the concepts of Systems Thinking. These methodologies are generally associated with a particular System [[Paradigm (glossary)]] or way of thinking, which has a strong influence on the three aspects of a Systems Approach described above.  
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One topic that has received significant attention in the systems science community is the analysis and comparison of methodologies which implement a systems approach. A methodology is a body of tools, procedures, and methods applied to a problem situation, ideally derived from a theoretical {{Term|Framework (glossary)|framework}}. These describe structured approaches to problem understanding and/or resolution, making use of some of the {{Term|Concept (glossary)|concepts}} of {{Term|Systems Thinking (glossary)|systems thinking}}. These methodologies are generally associated with a particular system {{Term|Paradigm (glossary)|paradigm}} or way of thinking, which has a strong influence on the three aspects of a systems approach described above.  
  
The most widely used groups of methodologies are as follows, see also [[History of Systems Science]]:
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The most widely used groups of methodologies are as follows (see also [[History of Systems Science]]):
  
#[[Hard System (glossary)]] methodologies, (Checkland 1978), set out to select an efficient means to achieve a predefined and agreed end.
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* {{Term|Hard System (glossary)|Hard system}} methodologies (Checkland 1978) set out to select an efficient means to achieve a predefined and agreed end.
#[[Soft System (glossary)]] methodologies, (Checkland 1999), are interactive and participatory approaches to assist groups of diverse participants to alleviate a complex, problematic situation of common interest.
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* {{Term|Soft System (glossary)|Soft system}} methodologies (Checkland 1999) are interactive and participatory approaches to assist groups of diverse participants to alleviate a complex, problematic situation of common interest.
#[[Critical Systems Thinking (glossary)]] methodologies,(Jackson 1985), attempts to provide a framework in which appropriate hard and soft methods can be applied as appropriate to the situation under investigation.
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* {{Term|Critical Systems Thinking (glossary)|Critical systems thinking}} methodologies (Jackson 1985) attempt to provide a framework in which appropriate hard and soft methods can be applied as appropriate to the situation under investigation.
  
===Systems dynamics===
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===Systems Dynamics===
  
Systems Dynamics (SD) uses some of the ideas of cybernetics to consider the behavior of systems as a whole in their environment. SD was developed by Jay Forrester in the 1960’s He was interested in modeling the dynamic behavior of systems such as populations in cities, industrial supply chains.
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Systems dynamics (SD) uses some of the ideas of {{Term|Cybernetics (glossary)|cybernetics}} to consider the {{Term|Behavior (glossary)|behavior}} of systems as a whole in their {{Term|Environment (glossary)|environment}}. SD was developed by Jay Forrester in the 1960’s. He was interested in {{Term|Model (glossary)|modeling}} the dynamic behavior of systems such as populations in cities, or industrial supply chains.
  
System dynamics, (Forrester 1961), is an approach to understanding the behaviour of complex systems over time. It deals with internal feedback loops and time delays that affect the behaviour of the entire system. The main element of SD are:  
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System dynamics (Forrester 1961) is an approach to understanding the behavior of complex systems over time. It deals with internal feedback loops and time delays that affect the behavior of the entire system. The main {{Term|Element (glossary)|elements}} of SD are:  
  
*The understanding of the dynamic interactions in a problem or solution as a system of feedback loops. modelled using a Causal Loop Diagram
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* The understanding of the dynamic interactions in a problem or solution as a system of feedback loops, modeled using a Causal Loop Diagram.
*Quantative modelling of system performance as an accumulation of Stocks (any entity or property which varies over time) and Flows (representations of the rate of change of a stock.
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* Quantitative modeling of system performance as an accumulation of stocks (any entity or property which varies over time) and flows (representations of the rate of change of a stock).
*The creation of dynamic simulations, exploring how the value of key parameters change over time.  A wide range pof software tools are available to support this.
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*The creation of dynamic simulations, exploring how the {{Term|Value (glossary)|value}} of key parameters change over time.  A wide range of {{Term|Software (glossary)|software}} tools are available to support this.
  
These elements help describe how even seemingly simple systems display baffling nonlinearity.
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These elements help describe how even seemingly simple systems display baffling non-linearity.
  
 
===Hard Systems Methodologies===
 
===Hard Systems Methodologies===
  
Checkland (Checkland 1975) classifies [[Hard System (glossary)|hard system (glossary)]] methodologies, which set out to select an efficient means to achieve a predefined end, under the following headings:  
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Checkland (1975) classifies {{Term|Hard System (glossary)|hard system (glossary)}} methodologies, which set out to select an efficient means to achieve a predefined end, under the following headings:  
  
#System Analysis, the systematic appraisal of the costs and other implications of meeting a defined requirement in various ways.  
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* {{Term|System Analysis (glossary)|Systems Analysis}} - the systematic appraisal of the costs and other implications of meeting a defined requirement in various ways.  
#Systems Engineering, the set of activities that together lead to the creation of a complex man-made entity and/or the procedures and information flows associated with its operation.  
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* {{Term|Systems Engineering (glossary)|Systems Engineering}} (SE) - the set of activities that together lead to the creation of a complex man-made entity and/or the procedures and information flows associated with its operation.  
  
Operational Research is also considered a hard system approach, closely related to the Systems Analysis approach developed by the Rand Corporation, in which solutions are known but the best combinations of these solutions must be found. There is some debate as to whether System Dynamics is a hard approach, which is used to assess the objective behavior of real situations. Many application of SD have focused on the system, however it can and has also be used as part of a soft approach including the modelling of subjective perceptions (Lane 2000).  
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Operational Research is also considered a hard system approach, closely related to the systems analysis approach developed by the Rand Corporation, in which solutions are known but the best combinations of these solutions must be found. There is some debate as to whether system dynamics is a hard approach, which is used to assess the objective behavior of real situations. Many applications of SD have focused on the system, however it can and has also been used as part of a soft approach including the modeling of subjective perceptions (Lane 2000).  
  
Systems Engineering allows for the creation of new solution systems, based upon available technologies. This hard view of systems engineering as a solution focused approach applied to large, complex and technology focused solutions, is exemplified by (Jenkins 1969; Hall 1962) and early defense and aerospace standards.  
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SE allows for the creation of new solution systems, based upon available technologies. This hard view of SE as a solution focused approach applied to large, complex and technology focused solutions, is exemplified by (Jenkins 1969; Hall 1962) and early defense and aerospace standards.  
  
NOTE: Historically, the systems engineering discipline was primarily aimed at developing, modifying or supporting hard systems. More recent developments in systems engineering have incorporated problem focused thinking and agile solution approaches. It is this view of SE that is described in this SEBoK.  
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It should be noted that historically the SE discipline was primarily aimed at developing, modifying or supporting hard systems. More recent developments in SE have incorporated problem focused thinking and agile solution approaches. It is this view of SE that is described in the SEBoK.
  
All of these hard approaches can use systems thinking to ensure complete and viable solutions are created and/or as part of the solution optimization process. These approaches are appropriate to [[Unitary (glossary)]] problems, but not when the problem situation or solution technologies are unclear.
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All of these hard approaches can use systems thinking to ensure complete and viable solutions are created and/or as part of the solution optimization process. These approaches are appropriate to {{Term|Unitary (glossary)|unitary}} problems, but not when the problem situation or solution technologies are unclear.
  
===Soft Systems and Problem Structured Methods===
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===Soft Systems and Problem Structuring Methods===
  
Problem Structuring Methods (PSM) are interactive and participatory approaches to assist groups of diverse participants to alleviate a complex, problematic situation of common interest. Typically the hardest element of the situation is framing the issues which constitute the problem (Minger and Resenhead 2004).  
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Problem Structuring Methods (PSM) are interactive and participatory approaches to assist groups of diverse participants to alleviate a complex, problematic situation of common interest. Typically, the hardest element of the situation is framing the issues which constitute the problem (Minger and Resenhead 2004).  
  
PSM use systems and systems thinking as an abstract framework for investigation, rather than a structure for creating solutions. Systems descriptions are used to understand the current situation and describe an idealized future. Interventions directly in the current organization to move towards the idea recognize that the assumptions and mental models of the participants are an important obstruction to change and that these differing views cannot be dismissed but must form part of the intervention approach.  
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PSM use systems and systems thinking as an abstract framework for investigation, rather than a structure for creating solutions. Systems descriptions are used to understand the current situation and describe an idealized future. Interventions directly in the current organization to move towards the idea recognize that the assumptions and mental models of the participants are an important obstruction to change, and that these differing views cannot be dismissed but instead must form part of the intervention approach.  
  
Peter Checkland’s action research program, see [[Systems Science]], in the 1980‘s forms the basis of work by Checkland, Wilson and others in the development of [[Soft Systems Methodology (glossary)]] (SSM) (Checkland 1999; Wilson 2001). SSM formalizes the idea of a soft approach using systemic thinking to expose the issues in a problem situation and guide interventions to reduce them. SSM provides a framework of ideas and models to help guide participants through this systemic thinking.  
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Peter Checkland’s action research program (see [[Systems Science]]) in the 1980‘s forms the basis of work by Checkland, Wilson and others in the development of {{Term|Soft Systems Methodology (glossary)}} (SSM) (Checkland 1999; Wilson 2001). SSM formalizes the idea of a soft approach using systemic thinking to expose the issues in a problem situation and guide interventions to reduce them. SSM provides a framework of ideas and models to help guide participants through this systemic thinking.  
  
Other PSM approaches include Interactive Planning Approach (Ackoff 1981); Social Systems Design (Churchman 1968), and Strategic Assumptions Surfacing and Testing (Mason and Mitroff 1981).  
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Other PSM approaches include interactive planning approach (Ackoff 1981), social systems design (Churchman 1968), and strategic assumptions surfacing and testing (Mason and Mitroff 1981).  
  
SSM and other soft approaches use systems thinking to ensure problem situations are fully explored and resolved. These approaches are appropriate to [[Pluralist (glossary)|pluralist (glossary)]] problems. Critics of SSM suggest that it does not consider the process of intervention, and in particular how differences in power between individuals and social groups impacts the effectiveness of interventions.
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SSM and other soft approaches use systems thinking to ensure problem situations are fully explored and resolved. These approaches are appropriate to {{Term|Pluralist (glossary)|pluralist}} problems. Critics of SSM suggest that it does not consider the process of intervention, and in particular how differences in power between individuals and social groups impact the effectiveness of interventions.
  
===Critical systems thinking and Multimethodology===
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===Critical Systems Thinking and Multi-Methodology===
  
The development of a range of hard and soft methods naturally leads to the question of which method to apply when (Jackson 1989). [[Critical Systems Thinking (glossary)]] (CST) or '''Critical Management Science''' Jackson (Jackson 1985) attempts to deal with this question.  
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The development of a range of hard and soft methods naturally leads to the question of which method to apply in what set of circumstances (Jackson 1989). {{Term|Critical Systems Thinking (glossary)|Critical systems thinking}} (CST) or '''Critical Management Science''' (Jackson 1985) attempts to deal with this question.  
  
The word critical is used in two ways. Firstly, critical thinking considers the limits of knowledge and investigates the limits and assumptions of hard and soft systems, as discussed in the above sections. From this comes frameworks and meta-methodology for when to apply different methods such as '''Total Systems Intervention''' (TSI) (Flood and Jackson 1991). Critical or “pluralist” or “pragmatic” '''Multi-Methodology''' approaches take this aspect of critical thinking one stage further to recognize the value of combining techniques from several hard, soft , or custom methods as needed (Mingers and Gill 1997). Many in the systems science community believe that the multi-methodology approach has been accepted as the de facto systems approach, and that the challenges now are in refining tools and methods to support it.
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The word critical is used in two ways. Firstly, critical thinking considers the limits of knowledge and investigates the limits and assumptions of hard and soft systems, as discussed in the above sections. From this comes frameworks and meta-methodology that establish when to apply different methods such as '''total systems intervention''' (TSI) (Flood and Jackson 1991). Critical, “pluralist,” or “pragmatic” '''multi-methodology''' approaches take this aspect of critical thinking one stage further to recognize the value of combining techniques from several hard, soft , or custom methods as needed (Mingers and Gill 1997). Many in the systems science community believe that the multi-methodology approach has been accepted as the de facto systems approach and that the challenges now are in refining tools and methods to support it.
  
'''Churchman''' (Churchman, 1979) and others have also considered broader ethics political and social questions related to management science, with regards to the relative power and responsibility of the participants in system interventions. The second aspect of critical thinking considers the ethical, political and coercive dimension in Jackson's SOSM framework (Jackson 2003) and the role of system thinking in society.
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'''Churchman''' (1979) and others have also considered broader {{Term|Ethics (glossary)|ethics}}, political and social questions related to management science, with regards to the relative power and responsibility of the participants in system interventions. The second aspect of critical thinking considers the ethical, political, and coercive dimension in Jackson's System of Systems Methodologies (SOSM) framework (Jackson 2003) and the role of system thinking in society.
  
 
==Selecting Systems Methodologies==
 
==Selecting Systems Methodologies==
  
'''Jackson''' proposes a frame for considering which approach should be applied, please see: [http://www.systemswiki.org/index.php?title=System_of_Systems_Methodologies_(SOSM) Jackson's Framework]. In Jackson's framework the following definitions apply to the participants involved in solving the problem:
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'''Jackson''' proposes a frame for considering which approach should be applied (please see [http://www.systemswiki.org/index.php?title=System_of_Systems_Methodologies_(SOSM) Jackson's Framework]). In Jackson's framework, the following definitions apply to the participants involved in solving the problem:
*[[Unitary (glossary)]]: A problem situation in which participants "have similar values, beliefs and interests. They share common purposes and are all involved, in one way or another, in decision-making about how to realize their agreed objectives." (Jackson 2003, p. 19)
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* {{Term|Unitary (glossary)|Unitary}}: A problem situation in which participants "have similar values, beliefs and interests. They share common purposes and are all involved, in one way or another, in decision-making about how to realize their agreed objectives." (Jackson 2003, 19)
*[[Pluralist (glossary)]]: A problem situation involving participants in which "although their basic interests are compatible, they do not share the same values and beliefs. Space needs to be made available within which debate, disagreement, even conflict, can take place. If this is done, and all feel they have been involved in decision-making, then accommodations and compromises can be found. Participants will come to agree, at least temporarily, on productive ways forward and will act accordingly." (Jackson 2003, p. 19)
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* {{Term|Pluralist (glossary)|Pluralist}}: A problem situation involving participants in which "although their basic interests are compatible, they do not share the same values and beliefs. Space needs to be made available within which debate, disagreement, even conflict, can take place. If this is done, and all feel they have been involved in decision-making, then accommodations and compromises can be found. Participants will come to agree, at least temporarily, on productive ways forward and will act accordingly." (Jackson 2003, 19)
*[[Coercive (glossary)]]: A problem situation in which the participants "have few interests in common and, if free to express them, would hold conficting values and beliefs. Compromise is not possible and so no agreed objectives direct action. Decisions are taken on the basis of who has most power and various forms of coercion employed to ensure adherence to commands." (Jackson 2003, p. 19)
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* {{Term|Coercive (glossary)|Coercive}}: A problem situation in which the participants "have few interests in common and, if free to express them, would hold conflicting values and beliefs. Compromise is not possible and so no agreed objectives direct action. Decisions are taken on the basis of who has most power and various forms of coercion employed to ensure adherence to commands." (Jackson 2003, 19)
  
Jackson's framework suggests that for simple and complex systems with unitary participants, hard and dynamic systems thinking applies, respectively.  For simple and complex systems with pluralist participants, soft systems thinking applies. For simple and complex systems with coercive participants, '''emancipatory''' and [[Postmodernist (glossary)]] system thinking applies, respectively.  These thinking approaches consider all attempts to look for system solutions to be temporary and ineffective in situations where the power of individuals and groups of people dominate any system structures we create.  They advocate an approach which encourages diversity, free thinking and creativity of individuals and in the organization's structures. Thus, modern system thinking has the breadth needed to deal with a broad range of complex problems and solutions.
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Jackson's framework suggests that for simple and complex systems with unitary participants, hard and dynamic systems thinking applies, respectively.  For simple and complex systems with pluralist participants, soft systems thinking applies. For simple and complex systems with coercive participants, '''emancipatory''' and {{Term|Postmodernist (glossary)|postmodernist}} system thinking applies, respectively.  These thinking approaches consider all attempts to look for system solutions to be temporary and ineffective in situations where the power of individuals and groups of people dominate any system structures we create.  They advocate an approach which encourages diversity, free-thinking and creativity of individuals and in the organization's structures. Thus, modern systems thinking has the breadth needed to deal with a broad range of complex problems and solutions.
  
These ideas sit at the extreme of system thinking as a tool for challenging assumptions in and stimulating innovative solutions in problem solving. Jackson (Jackson 2003) identifies the work of some authors who have included these ideas into their systems approach.
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These ideas sit at the extreme of system thinking as a tool for challenging assumptions and stimulating innovative solutions in problem solving. Jackson (2003) identifies the work of some authors who have included these ideas into their systems approach.
  
 
==References==
 
==References==
  
 
===Works Cited===
 
===Works Cited===
Bertalanffy, L. 1968. General Systems Theory. New York, Ny, USA: George Braziller, Inc.
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Ackoff, R.L. 1981. ''Creating the Corporate Future''. New York, NY, USA: Wiley and Sons.  
 
 
Ackoff, R.L. 1981. Creating the Corporate Future. New York, NY, USA: Wiley and Sons.  
 
  
Checkland, P. 1975. "The Origins and Nature of “Hard” Systems Thinking." Journal of Applied Systems Analysis, 5(2): 99-110.  
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Bertalanffy, L. 1968. ''General System Theory: Foundations, Development, Applications''. New York, NY, USA: George Braziller, Inc.  
  
Checkland, P. 1999. Systems Thinking, Systems Practice, New York, NY, USA: John Wiley & Sons.
 
  
Churchman, C.W. 1968. The Systems Approach. New York, NY, USA: Dell Publishing.  
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Checkland, P. 1978. "The origins and nature of “hard” systems thinking," ''Journal of Applied Systems Analysis,'' vol. 5, no. 2, pp. 99-110.  
  
Churchman, C. West. 1979. "The Systems Approach and Its Enemies". New York: Basic Books.  
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Checkland, P. 1999. ''Systems Thinking, Systems Practice.'' New York, NY, USA: John Wiley & Sons.  
  
Flood, R. and M. Jackson. 1991. Creative Problem Solving: Total Systems Intervention. London, UK: Wiley.  
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Churchman, C.W. 1968. ''The Systems Approach''. New York, NY, USA: Dell Publishing.  
  
Forrester, J. 1961. Industrial Dynamics. Cambridge, MA, USA: MIT Press.  
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Churchman, C. W.. 1979. ''The Systems Approach and Its Enemies''. New York: Basic Books.  
  
Hall, A.D. 1962. A Methodology for Systems Engineering. New York, NY, USA: Van Nostrand Reinhold.  
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Flood, R. and M. Jackson. 1991. ''Creative Problem Solving: Total Systems Intervention''. London, UK: Wiley.  
  
Hybertson, D, 2009. Model-oriented Systems Engineering Science: A Unifying Framework for Traditional and Complex Systems (CRC Complex and Enterprise Systems Engineering)
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Forrester, J. 1961. ''Industrial Dynamics''. Cambridge, MA, USA: MIT Press.  
  
Jackson, M. 1985. "Social Systems Theory and Practice: the Need for a Critical Approach." International Journal of General Systems. 10: 135-151.  
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Hall, A.D. 1962. ''A Methodology for Systems Engineering''. New York, NY, USA: Van Nostrand Reinhold.  
  
Jackson, M. 1989. "Which Systems Methodology When? Initial Results from a Research Program." In: R Flood, M Jackson and P Keys (eds). Systems Prospects: the Next Ten Years of Systems Research. New York, NY, USA: Plenum.  
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Hybertson, D, 2009. ''Model-Oriented Systems Engineering Science: A Unifying Framework for Traditional and Complex Systems.'' Series in Complex and Enterprise Systems Engineering. Boston, MA, USA: Auerbach Publications.
  
Jackson, M. 2003. Systems Thinking: Creating Holisms for Managers. Chichester, UK: Wiley.  
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Jackson, M. 1985. "Social systems theory and practice: The need for a critical approach," ''International Journal of General Systems,'' vol. 10, pp. 135-151.  
  
Jenkins, G.M. 1969. The Systems Approach. In Beishon, J. and G. Peters (eds.), Systems Behavior, 2nd ed. New York, NY, USA: Harper and Row.  
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Jackson, M. 1989. "Which systems methodology when? Initial results from a research program," in R Flood, M Jackson and P Keys (eds). ''Systems Prospects: The Next Ten Years of Systems Research''. New York, NY, USA: Plenum.  
  
Kuhn, T.S. ''The Structure of Scientific Revolutions.'' Chicago: University of Chicago Press, 1962
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Jackson, M. 2003. ''Systems Thinking: Creating Holisms for Managers''. Chichester, UK: Wiley.
  
Lane, D. 2000  “Should System Dynamics be Described as a `Hard' or `Deterministic' Systems Approach?” Systems Research and Behavioral Science 17, 3–22 (2000) John Wiley & Sons, Ltd.
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Jenkins, G.M. 1969. "The Systems Approach." In J. Beishon and G. Peters (eds.), ''Systems Behavior'', 2nd ed. New York, NY, USA: Harper and Row.  
  
Mason, R.O. and I.I. Mitroff. 1981. Challenging Strategic Planning Assumptions: Theory, Case and Techniques. New York, NY, USA: Wiley and Sons.  
+
Lane, D. 2000. “Should system dynamics be described as a `hard' or `deterministic' systems approach?” ''Systems Research and Behavioral Science,'' vol. 17, pp. 3–22.
  
Mingers, J. and A. Gill. 1997. Multimethodology: Theory and Practice of Combining Management Science Methodologies. Chichester, UK: Wiley.  
+
Mason, R.O. and I.I. Mitroff. 1981. ''Challenging Strategic Planning Assumptions: Theory, Case and Techniques''. New York, NY, USA: Wiley and Sons.  
  
Mingers, J. and J. Rosenhead. 2004. "Problem Structuring Methods in Action." European Journal of Operations Research. 152(3) (Feb. 2004): 530-554.  
+
Mingers, J. and A. Gill. 1997. ''Multimethodology: Theory and Practice of Combining Management Science Methodologies''. Chichester, UK: Wiley.  
  
Senge, P. M. 1990, 2006. The Fifth Discipline: The Art and Practice of the Learning Organization. New York, Doubleday/Currency.  
+
Senge, P.M. 1990, 2006. ''The Fifth Discipline: The Art and Practice of the Learning Organization''. New York, Doubleday/Currency.  
  
Wilson, B. 2001. Soft Systems Methodology—Conceptual Model Building and Its Contribution. New York, NY, USA: J.H.Wiley.
+
Wilson, B. 2001. ''Soft Systems Methodology—Conceptual Model Building and Its Contribution''. New York, NY, USA: J.H.Wiley.
  
 
===Primary References===
 
===Primary References===
  
Checkland, P. 1999. [[Systems Thinking, Systems Practice]], New York, NY, USA: John Wiley & Sons.  
+
Checkland, P. 1999. ''[[Systems Thinking, Systems Practice]].'' New York, NY, USA: John Wiley & Sons.  
  
Forrester, J. 1961. [[Industrial Dynamics]]. Cambridge, MA, USA: MIT Press.  
+
Forrester, J. 1961. ''[[Industrial Dynamics]]''. Cambridge, MA, USA: MIT Press.  
  
Jackson, M. 1985. [[Social Systems Theory and Practice]]: the Need for a Critical Approach. International Journal of General Systems 10: 135-151.
+
Jackson, M. 1985. "[[Social Systems Theory and Practice|Social systems theory and practice]]: The need for a critical approach," ''International Journal of General Systems,'' vol. 10, pp. 135-151.
  
 
===Additional References===
 
===Additional References===
  
Jackson, M.C. and Keys, P. 1984. "Towards a System of Systems Methodologies." The Journal of the Operational Research Society. 35(6) (Jun. 1984): 473-486.  
+
Jackson, M.C. and P. Keys. 1984. "Towards a system of systems methodologies," ''The Journal of the Operational Research Society,'' vol. 35, no. 6, June,, pp. 473-486.  
  
Sterman, John D. (2001). "System dynamics modeling: Tools for learning in a complex world". California management review 43 (4): 8–25.  
+
Mingers, J. and J. Rosenhead. 2004. "Problem structuring methods in action," ''European Journal of Operations Research,'' vol. 152, no. 3, February, pp. 530-554.
 +
Sterman, J.D. 2001. "System dynamics modeling: Tools for learning in a complex world," ''California Management Review,'' vol. 43, no. 4, pp. 8–25.  
  
 
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<center>[[History of Systems Science|< Previous Article]] | [[Systems Science|Parent Article]] | [[Complexity|Next Article >]]</center>
  
==Comments from SEBoK 0.5==
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<center>'''SEBoK v. 2.10, released 06 May 2024'''</center>
This article is new to the SEBoK for version 0.75. As such, there are no associated 0.5 comments. Because of this, it is especially important for reviewers to provide feedback on this article.  Please see the discussion prompts below.
 
  
 
[[Category: Part 2]][[Category: Topic]][[Category:Systems Science]]
 
[[Category: Part 2]][[Category: Topic]][[Category:Systems Science]]
{{DISQUS}}
 

Latest revision as of 22:37, 2 May 2024


Lead Author: Rick Adcock, Contributing Authors: Scott Jackson, Janet Singer, Duane Hybertson


This article is part of the Systems Science knowledge area (KA). It presents issues in the comparison and analysis of classic systems approachessystems approaches developed by the systems sciencesystems science community. Some of these ideas contribute to basic theory and methods that are used in systems thinkingsystems thinking discussed in the Systems Thinking KA.

What is a Systems Approach?

In Bertalanffy's introduction to his 1968 book General System Theory (GST), he characterizes a systems approach as:

A certain objective is given; to find ways and means for its realization requires the system specialist (or team of specialists) to consider alternative solutions and to choose those promising optimization at maximum efficiency and minimum cost in a tremendously complex network of interactions. (Bertalanffy 1968, 4)

He goes on to list as possible elements of a systems approach: “classical” systems theory (differential equations), computerization and simulationsimulation, compartment theory, set theory, graph theory, net theory, cyberneticscybernetics, information theory, theory of automata, game theory, decision theory, queuing theory, and modelsmodels in ordinary language.

This description is similar to what Warren Weaver identified as the methods used successfully by “mixed teams” during World War II (WWII) on “problems of organized complexity”. However, some conditions that had contributed to success during wartime did not hold after the war, such as a clear focus on well-defined common goals that motivated participants to work across disciplinary boundariesboundaries.

By the early 1970’s, there was growing disillusionment with the promise that a systems approach would provide easy solutionssolutions for all complexcomplex problemsproblems. There was particular criticism from some, including pioneers of Operations Research and Management Science (ORMS) like Ackoff and Churchman, that reliance on rote mathematical methods to identify optimal solutions among fixed alternatives had become just as inflexible and unimaginative an approach to complex problems as whatever it had replaced. Interest grew in examining and comparing methods and methodologies to better understand what could help ensure the best thinking and learning in terms of systems in systems approaches to practice.

Issues in Systems Approaches

A systems approach is strongly associated with systems thinkingsystems thinking and how it helps to guide systems practice. In What is Systems Thinking? the key ideas of considering a systemsystem holisticallyholistically, setting a boundaryboundary for a problemproblem/solutionsolution of interest, and considering the resulting system-of-interestsystem-of-interest from outside its boundary are identified (Churchman 1979; Senge 2006).

A systems approach can view a system as a “holon” – an entity that is itself a “whole system” that interacts with a mosaic of other holons in its wider environment (Hybertson 2009), while also being made up of interacting parts. We can use this modelmodel recursivelyrecursively – each part of the system may be a system in its own right, and can itself be viewed both as an entity as seen from outside, and as a set of interacting parts. This model also applies in upwards recursion, so the original “system-of-interest” is an interacting part of one or more wider systems.

This means that an important skill in a systems approach is to identify the “natural holons” in the problem situation and solution systems and to make the partitioning of responsibilities match the “natural holons,” so as to minimize the coupling between parallel activities when applying a solution. This is the “cohesive/loose coupling” heuristicheuristic that has been around for a long time in many design disciplines.

Another consequence of the holistic nature of a systems approach is that it considers not only a problem situation and a solution system but also the system created and deployed to apply one to the other. A systems approach must consider both the boundary of the system of concern as well as the boundary of the system inquiry (or model). Real systems are always open, i.e., they interact with their environmentenvironment or supersystem(s). On the other hand, real models are always “closed” due to resource constraintsconstraints — a fixed boundary of consideration must be set. Thus, there is an ongoing negotiation to relate the two in systems practice and the judgment to do so is greatly helped by an appreciation of the difference between them.

Thus, a systems approach can be characterized by how it considers problems, solutions and the problem resolution process itself:

  • Consider problems holistically, setting problem boundaries though understanding of natural system relationships and trying to avoid unwanted consequences.
  • Create solutions based on sound system principles, in particular creating system structures which reduce organized complexitycomplexity and unwanted emergentemergent properties.
  • Use understanding, judgment and models in both problem understanding and solution creation, while understanding the limitations of such views and models.

Systems Methodologies

One topic that has received significant attention in the systems science community is the analysis and comparison of methodologies which implement a systems approach. A methodology is a body of tools, procedures, and methods applied to a problem situation, ideally derived from a theoretical frameworkframework. These describe structured approaches to problem understanding and/or resolution, making use of some of the conceptsconcepts of systems thinkingsystems thinking. These methodologies are generally associated with a particular system paradigmparadigm or way of thinking, which has a strong influence on the three aspects of a systems approach described above.

The most widely used groups of methodologies are as follows (see also History of Systems Science):

  • Hard systemHard system methodologies (Checkland 1978) set out to select an efficient means to achieve a predefined and agreed end.
  • Soft systemSoft system methodologies (Checkland 1999) are interactive and participatory approaches to assist groups of diverse participants to alleviate a complex, problematic situation of common interest.
  • Critical systems thinkingCritical systems thinking methodologies (Jackson 1985) attempt to provide a framework in which appropriate hard and soft methods can be applied as appropriate to the situation under investigation.

Systems Dynamics

Systems dynamics (SD) uses some of the ideas of cyberneticscybernetics to consider the behaviorbehavior of systems as a whole in their environmentenvironment. SD was developed by Jay Forrester in the 1960’s. He was interested in modelingmodeling the dynamic behavior of systems such as populations in cities, or industrial supply chains.

System dynamics (Forrester 1961) is an approach to understanding the behavior of complex systems over time. It deals with internal feedback loops and time delays that affect the behavior of the entire system. The main elementselements of SD are:

  • The understanding of the dynamic interactions in a problem or solution as a system of feedback loops, modeled using a Causal Loop Diagram.
  • Quantitative modeling of system performance as an accumulation of stocks (any entity or property which varies over time) and flows (representations of the rate of change of a stock).
  • The creation of dynamic simulations, exploring how the valuevalue of key parameters change over time. A wide range of softwaresoftware tools are available to support this.

These elements help describe how even seemingly simple systems display baffling non-linearity.

Hard Systems Methodologies

Checkland (1975) classifies hard system (glossary)hard system (glossary) methodologies, which set out to select an efficient means to achieve a predefined end, under the following headings:

  • Systems AnalysisSystems Analysis - the systematic appraisal of the costs and other implications of meeting a defined requirement in various ways.
  • Systems EngineeringSystems Engineering (SE) - the set of activities that together lead to the creation of a complex man-made entity and/or the procedures and information flows associated with its operation.

Operational Research is also considered a hard system approach, closely related to the systems analysis approach developed by the Rand Corporation, in which solutions are known but the best combinations of these solutions must be found. There is some debate as to whether system dynamics is a hard approach, which is used to assess the objective behavior of real situations. Many applications of SD have focused on the system, however it can and has also been used as part of a soft approach including the modeling of subjective perceptions (Lane 2000).

SE allows for the creation of new solution systems, based upon available technologies. This hard view of SE as a solution focused approach applied to large, complex and technology focused solutions, is exemplified by (Jenkins 1969; Hall 1962) and early defense and aerospace standards.

It should be noted that historically the SE discipline was primarily aimed at developing, modifying or supporting hard systems. More recent developments in SE have incorporated problem focused thinking and agile solution approaches. It is this view of SE that is described in the SEBoK.

All of these hard approaches can use systems thinking to ensure complete and viable solutions are created and/or as part of the solution optimization process. These approaches are appropriate to unitaryunitary problems, but not when the problem situation or solution technologies are unclear.

Soft Systems and Problem Structuring Methods

Problem Structuring Methods (PSM) are interactive and participatory approaches to assist groups of diverse participants to alleviate a complex, problematic situation of common interest. Typically, the hardest element of the situation is framing the issues which constitute the problem (Minger and Resenhead 2004).

PSM use systems and systems thinking as an abstract framework for investigation, rather than a structure for creating solutions. Systems descriptions are used to understand the current situation and describe an idealized future. Interventions directly in the current organization to move towards the idea recognize that the assumptions and mental models of the participants are an important obstruction to change, and that these differing views cannot be dismissed but instead must form part of the intervention approach.

Peter Checkland’s action research program (see Systems Science) in the 1980‘s forms the basis of work by Checkland, Wilson and others in the development of soft systems methodologysoft systems methodology (SSM) (Checkland 1999; Wilson 2001). SSM formalizes the idea of a soft approach using systemic thinking to expose the issues in a problem situation and guide interventions to reduce them. SSM provides a framework of ideas and models to help guide participants through this systemic thinking.

Other PSM approaches include interactive planning approach (Ackoff 1981), social systems design (Churchman 1968), and strategic assumptions surfacing and testing (Mason and Mitroff 1981).

SSM and other soft approaches use systems thinking to ensure problem situations are fully explored and resolved. These approaches are appropriate to pluralistpluralist problems. Critics of SSM suggest that it does not consider the process of intervention, and in particular how differences in power between individuals and social groups impact the effectiveness of interventions.

Critical Systems Thinking and Multi-Methodology

The development of a range of hard and soft methods naturally leads to the question of which method to apply in what set of circumstances (Jackson 1989). Critical systems thinkingCritical systems thinking (CST) or Critical Management Science (Jackson 1985) attempts to deal with this question.

The word critical is used in two ways. Firstly, critical thinking considers the limits of knowledge and investigates the limits and assumptions of hard and soft systems, as discussed in the above sections. From this comes frameworks and meta-methodology that establish when to apply different methods such as total systems intervention (TSI) (Flood and Jackson 1991). Critical, “pluralist,” or “pragmatic” multi-methodology approaches take this aspect of critical thinking one stage further to recognize the value of combining techniques from several hard, soft , or custom methods as needed (Mingers and Gill 1997). Many in the systems science community believe that the multi-methodology approach has been accepted as the de facto systems approach and that the challenges now are in refining tools and methods to support it.

Churchman (1979) and others have also considered broader ethicsethics, political and social questions related to management science, with regards to the relative power and responsibility of the participants in system interventions. The second aspect of critical thinking considers the ethical, political, and coercive dimension in Jackson's System of Systems Methodologies (SOSM) framework (Jackson 2003) and the role of system thinking in society.

Selecting Systems Methodologies

Jackson proposes a frame for considering which approach should be applied (please see Jackson's Framework). In Jackson's framework, the following definitions apply to the participants involved in solving the problem:

  • UnitaryUnitary: A problem situation in which participants "have similar values, beliefs and interests. They share common purposes and are all involved, in one way or another, in decision-making about how to realize their agreed objectives." (Jackson 2003, 19)
  • PluralistPluralist: A problem situation involving participants in which "although their basic interests are compatible, they do not share the same values and beliefs. Space needs to be made available within which debate, disagreement, even conflict, can take place. If this is done, and all feel they have been involved in decision-making, then accommodations and compromises can be found. Participants will come to agree, at least temporarily, on productive ways forward and will act accordingly." (Jackson 2003, 19)
  • CoerciveCoercive: A problem situation in which the participants "have few interests in common and, if free to express them, would hold conflicting values and beliefs. Compromise is not possible and so no agreed objectives direct action. Decisions are taken on the basis of who has most power and various forms of coercion employed to ensure adherence to commands." (Jackson 2003, 19)

Jackson's framework suggests that for simple and complex systems with unitary participants, hard and dynamic systems thinking applies, respectively. For simple and complex systems with pluralist participants, soft systems thinking applies. For simple and complex systems with coercive participants, emancipatory and postmodernistpostmodernist system thinking applies, respectively. These thinking approaches consider all attempts to look for system solutions to be temporary and ineffective in situations where the power of individuals and groups of people dominate any system structures we create. They advocate an approach which encourages diversity, free-thinking and creativity of individuals and in the organization's structures. Thus, modern systems thinking has the breadth needed to deal with a broad range of complex problems and solutions.

These ideas sit at the extreme of system thinking as a tool for challenging assumptions and stimulating innovative solutions in problem solving. Jackson (2003) identifies the work of some authors who have included these ideas into their systems approach.

References

Works Cited

Ackoff, R.L. 1981. Creating the Corporate Future. New York, NY, USA: Wiley and Sons.

Bertalanffy, L. 1968. General System Theory: Foundations, Development, Applications. New York, NY, USA: George Braziller, Inc.


Checkland, P. 1978. "The origins and nature of “hard” systems thinking," Journal of Applied Systems Analysis, vol. 5, no. 2, pp. 99-110.

Checkland, P. 1999. Systems Thinking, Systems Practice. New York, NY, USA: John Wiley & Sons.

Churchman, C.W. 1968. The Systems Approach. New York, NY, USA: Dell Publishing.

Churchman, C. W.. 1979. The Systems Approach and Its Enemies. New York: Basic Books.

Flood, R. and M. Jackson. 1991. Creative Problem Solving: Total Systems Intervention. London, UK: Wiley.

Forrester, J. 1961. Industrial Dynamics. Cambridge, MA, USA: MIT Press.

Hall, A.D. 1962. A Methodology for Systems Engineering. New York, NY, USA: Van Nostrand Reinhold.

Hybertson, D, 2009. Model-Oriented Systems Engineering Science: A Unifying Framework for Traditional and Complex Systems. Series in Complex and Enterprise Systems Engineering. Boston, MA, USA: Auerbach Publications.

Jackson, M. 1985. "Social systems theory and practice: The need for a critical approach," International Journal of General Systems, vol. 10, pp. 135-151.

Jackson, M. 1989. "Which systems methodology when? Initial results from a research program," in R Flood, M Jackson and P Keys (eds). Systems Prospects: The Next Ten Years of Systems Research. New York, NY, USA: Plenum.

Jackson, M. 2003. Systems Thinking: Creating Holisms for Managers. Chichester, UK: Wiley.

Jenkins, G.M. 1969. "The Systems Approach." In J. Beishon and G. Peters (eds.), Systems Behavior, 2nd ed. New York, NY, USA: Harper and Row.

Lane, D. 2000. “Should system dynamics be described as a `hard' or `deterministic' systems approach?” Systems Research and Behavioral Science, vol. 17, pp. 3–22.

Mason, R.O. and I.I. Mitroff. 1981. Challenging Strategic Planning Assumptions: Theory, Case and Techniques. New York, NY, USA: Wiley and Sons.

Mingers, J. and A. Gill. 1997. Multimethodology: Theory and Practice of Combining Management Science Methodologies. Chichester, UK: Wiley.

Senge, P.M. 1990, 2006. The Fifth Discipline: The Art and Practice of the Learning Organization. New York, Doubleday/Currency.

Wilson, B. 2001. Soft Systems Methodology—Conceptual Model Building and Its Contribution. New York, NY, USA: J.H.Wiley.

Primary References

Checkland, P. 1999. Systems Thinking, Systems Practice. New York, NY, USA: John Wiley & Sons.

Forrester, J. 1961. Industrial Dynamics. Cambridge, MA, USA: MIT Press.

Jackson, M. 1985. "Social systems theory and practice: The need for a critical approach," International Journal of General Systems, vol. 10, pp. 135-151.

Additional References

Jackson, M.C. and P. Keys. 1984. "Towards a system of systems methodologies," The Journal of the Operational Research Society, vol. 35, no. 6, June,, pp. 473-486.

Mingers, J. and J. Rosenhead. 2004. "Problem structuring methods in action," European Journal of Operations Research, vol. 152, no. 3, February, pp. 530-554. Sterman, J.D. 2001. "System dynamics modeling: Tools for learning in a complex world," California Management Review, vol. 43, no. 4, pp. 8–25.


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