An Introduction to Problem Structuring Methods

What's the Problem? An Introduction to Problem Structuring Methods JONATHAN ROSENHEAD

London school of Economics Houghton Street London WC2A 2AE England

OR's traditional problem-solving techniques offer remarkably little assistance in deciding what the problem is. New problem structuring methods (PSMs) provide decision makers with systematic help in identifying an agreed framework for their problem. The result is either a well-defined project that can be addressed using traditional OR methods, or a clarification of the situation that enables those responsible to agree on a course of action. In principle, PSMs can provide analysts with greater access to strategic problems—those engaging multiple relatively independent decision makers. PSMs' transparent methods of representation can capture differing perceptions of the situation, to help generate a consensus or to facilitate negotiations.

P

roblem structuring methods (PSMs)

a range of problem situations for which

are a broad group of problem-handling approaches whose purpose is to assist in structuring problems rather than directly with solving them. They are partieipative and interactive in character and in principle offer operations research access to

more classical OR techniques have limited applicability. Operations researchers have been developing and using individual problem structuring methods since the mid-1960s. However, only recently have they recognized

Copyright © 1996, Institute for Operations Research and the Management Sciences 0092-2102/96/2606/0117$01.25 This paper was refereed.

PROFESSIONAL—OR/MS IMPLEMENTATION PROBLEM DIAGNOSIS

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ROSENHEAD them as constituting a coherent field that is important for the current practice and future prospects of OR.

—The client organization was structured in a tight hierarchy; —Few of its members were analytically Limitations to the Orthodox Heritage sophisticated; Since the late 1960s, analysts have ac—The organization performed a welltively debated claims for the objectivity of defined repetitive task generating reliable OR/MS models and the limitations imdata; and posed on OR/MS practice by its —There was general consensus on prioriconcentration on well-defined problems. ties. Critics (for example, Ackoff [1979a], In the New York fire service, it had considCheckland [1983], and Churchman [1967]) erable impact; in the New York public noted the assumption behind standard OR health service, it suffered ignominious techniques that relevant factors, constraints, failure. and the objective function are both estabThe situations that satisfy the conditions lished in advance and consensual. ConsisGreenberger, Crenson, and Crissey identitent with this, standard formulations of OR fied are predominantly those in which unimethodology (for example, formulate, tary control is exercised over uncontentious model, test, solve, and implement) take as activities. Within these confines, the standtheir foundation the possibility of a single ard OR approach with its battery of poweruncontested representation of the problem ful techniques can be formidably effective. situation under consideration. Within this Many aspects of our complex and interframework, there is no intellectual impedi- locking social arrangements, in the absence ment to adopting optimization as the cenof such analytic inputs, could operate, if at terpiece of OR's technical repertoire. all, only ineffectually or with unreasonable waste of effort. This much is not in dispute. Critics have generally recognized that OR practice has been considerably more di- Many, however, have become concerned verse than this and in particular is far from that the exclusion of problem domains that dominated by considerations of optimality. violate some or all of the Greenberger conThey have argued, however, that the avail- ditions may be bad both for OR and for society at large. It is this concern that motiable tools and the accepted wisdom on vates and justifies the development of methodology give scant guidance to anaproblem structuring methods. lysts confronting less well-behaved situaDichotomies tions. An in-depth analysis by Greenberger, This analysis of the RAND experience Crenson, and Crissey [1976] of the RAND has already pointed to a dichotomy of Corporation's experience in its seven-year problem situations. Other commentators engagement with the problems of urban have made broadly parallel observations: government in New York City provides tame versus wicked problems [Rittel and supportive empirical evidence for this hyWebber 1973], problems versus messes pothesis. They found that the traditional [Ackoff 1981]. Schon [1987] captures this OR approach worked well where distinction graphically in his extended met-

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PROBLEM STRUCTURING METHODS aphor contrasting the "high ground," where problems are of great technical interest but of limited social importance, with the "swamp," where messy, confusing problems defy technical solution. In each case, the authors reach the same conclusion—that the methods for problem handling appropriate to pacified conditions do not transfer to more turbulent and problematic environments. Why this should be so emerges readily from a consideration of the nature of swamp conditions/messes/wicked problems. Typically there is a range of actors who are not in subordinate-superordinate relationships with each other; they have a considerable degree of autonomy. The different actors have their own interests and perspectives that lead them to pursue different objectives and to identify different factors as relevant. The potential is here for conflict, often exacerbated by the high levels of uncertainty that actors commonly have to endure about their own options, their likely consequences, the objectives and possible tactics of others, and so forth.

find than for their well-developed sensitivity-analysis routines, which a skilled craftsperson can use as sophisticated diagnostic instruments [Beale 1980]. Alternatively, Cyert [1981] suggests that more and yet more powerful analytic work will enable OR to "tame" these as yet ill-structured problems one by one. Decision analysts aim to extend the range of traditional analysis by incorporating subjective estimates of probabilities and of the values of outcomes when they cannot obtain objective information. Simon [1987] proposes that OR and artificial intelligence are complementary: where formulating problems precisely is impossible, we can develop expert systems capable of replicating human judgment. In their various ways, these prescriptions for OR's relevance problem outside its strict domain all amount to—more of the same treatment that generated the debilitating symptoms in the first place. The Characteristics of Problem Structuring Methods

Where no one can give orders, knowing an optimal solution is of Httle use, especially if it is the optimal solution to only one party's version of the problem. Where participants need to interact and negotiate to reach agreement, mathematics and computer algorithms that are hard to understand will tend to get in their way. Where uncertainty reigns, their confidence to make decisions may not be best advanced by the unambiguous specificities of a single OR formulation. Various ways around this difficulty have been proposed. Thus optimizing techniques may be valued less for the solutions they

Problem structuring methods provide a more radical response to the poor fit of the traditional OR approach for wicked problems—a response based on the characteristics of swamp conditions rather than on a preexisting investment in high-tech solution methods. These conditions suggest that decision makers are more likely to use a method and find it helpful if it accommodates multiple alternative perspectives, can facilitate negotiating a joint agenda, functions through interaction and iteration, and generates ownership of the problem formulation and its action implications through transparency of representation. These social requirements in turn have various technical implications. Representing problem com-

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ROSENHEAD plexity graphically (rather than algebraically or in tables of numerical results) will aid participation. The existence of multiple perspectives invalidates the search for an optimum; the need is rather for systematic exploration of the solution space. Lay people can generally express their judgments more meaningfully by choosing between discrete alternatives rather than across continuous variables. Estimating numerical probabilities will need to give way to identifying relevant possibilities. And alternative scenarios will substitute for future forecasts. The specification I have outlined for a decision-aiding technology more appropriate to messy, strategic problems eliminates much of the scope for advanced mathematics, probability theory, and complex algorithms (as practiced, for example, in decision analysis and the analytic hierarchy process). It identifies, rather, an alternative approach employing representation of relationships, symbolic manipulation, and limited quantification within a systematic framework.

switching freely between different modes or phases of the method in response to the dynamics of group discussion. Outputs may be visible (recommendations, plans, policies) or invisible (changed appreciations, shared values, better working relations). Of these, the visible outputs, given the differing agendas of participants, are likely to consist of partial rather than comprehensive commitments. Virtually all PSMs are designed for use by groups (although they have been widely appropriated as individual aids to problem clarification). The rationale for this is that if the problem situation involves multiple interest groups and plural rationalities under conditions in which no group can impose

The assumption is that relevant factors, constraints, and the objective function are established in advance.

These technical attributes are among the properties that unite the family of problemstructuring methods. Other common features concern the process of the engagement through which analysis assists decision making [Eden and Radford 1990]. This process is participative and interactive. Little or nothing happens in back rooms or black boxes; those who must take or recommend decisions are participants in or executants of the analysis. The purpose of the analysis is to elicit relevant knowledge and to reflect it back in structured form in an iterative process of problem construction. Typically PSMs operate nonlinearly.

its will, then negotiation of a way forward must involve representatives of these parties. Such arrangements are common both within organizations—the corporate board, interdepartmental task forces—and between them. Each member of the PSM family incorporates as a core element the explicit modeling of cause-effect relationships. This gives PSMs their unambiguous operational research identity. It distinguishes them, for example, from non-OR modes of group working, such as organizational development. PSMs can also be demarcated from other OR approaches that purport to tackle messy, ambitious problems (for example, the analytic hierarchy process). PSMs are

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PROBLEM STRUCTURING METHODS distinctive in their transparency of method, their restricted mathematization, and their focus on supporting judgment rather than representing it. These limits are imprecise and arguable: approaches developed for other or broader purposes (for example, spreadsheet models) can be used in a similar spirit. Methods that have some degree of similarity to PSMs, but which are best regarded as falling outside the category, include decision analysis, decision conferencing, PROMETHEE, scenario planning, system dynamics, and viable system diagnosis. Other parts of the PSM perimeter are bordered by the focus group approach, and by Rapid Rural Appraisal and other participative methods for third-world development planning. Some PSMs Summarized

perception among the actors about what actions are possible, about preferences between outcomes, and so forth [Bennett and Cropper 1986]. —Interactive planning (also called idealized planning) is a method with the ambitious aim of designing a desirable organizational future and ways of bringing it about. Analysts generate a reference scenario to demonstrate the dire consequences of not taking action. This motivates a participative process in which participants create an ideal design for the future of their organization. Other stages of the method deal with how to bring this future into existence [Ackoff 1979b].

I will attempt here the perhaps unwise task of summing up in a few sentences each the. intention, range of application, and mode of operation of methods that are the product of years of experience and of successive refinement. Eor more detailed coverage of particular methods, a first stop might be my introductory text [Rosenhead 1989], which contains accounts of six leading PSMs, each written by its principal developer. Another source is Flood and Jackson [1991], which offers summaries and critical discussion of a range of systems-based methods, not all of which could be described as PSMs. I will describe the methods in alphabetical order: —Hypergame analysis is an interactive approach to taking action in conflict situations. It emphasizes (1) exploring the pattern and nature of interactions between the actors, and (2) the effect of differences of

—Metagame analysis is an interactive method of analyzing cooperation and conflict among multiple actors. Analysts using supporting software work with one of the parties. They elicit from them decision options for the various actors, from which they construct possible future scenarios. Analysts and actors use these as a framework to explore their ability to stabilize the outcome at a more preferred scenario, by the use of threats and promises [Howard 1993]. —Robustness analysis is an approach that focuses on maintaining useful flexibility under uncertainty. In an interactive process, participants and analysts assess the compatibility of alternative initial commitments with possible futiire configurations of the system being planned for, and the performance of each configuration in feasible future environments. This enables them to compare the flexibility maintained by alternative initial commitments [Rosenhead 1980]. —Soft systems methodology (SSM) is a general method for system redesign. Par-


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ROSENHEAD ticipants build ideal-type conceptual models, one for each relevant world view. They compare them with perceptions of the existing system in order to generate debate about what changes are culturally feasible and systemically desirable [Checkland 1981; Checkland and Scholes 1990]. —Strategic assumption surfacing and testing is

a method for tackling ill-structured problems where differences of opinion about what strategy to pursue are preventing decision. Participants are divided into groups, each of which produces a preferred strategy and identifies the key assumptions on which it is based. The reunited groups debate these strategies and assumptions, mutually adjusting their assumptions on the way to an agreed solution [Mason and Mitroff 1981].

PSM Applications The extent of practical experience with these methods varies. Undoubtedly the methods that have the most extensive track record, in terms both of numbers of applications and of their migration away from their original developers, are SSM, SCA, and SODA. However, there has been very little systematic research into the extent of their penetration. An exception is the survey by Mingers and Taylor [1992], dealing exclusively with SSM. Though the sample was nonrandom, the survey did indicate large numbers of users, a wide dispersion of application types, and a considerable degree of user satisfaction.

(SODA) is a general problem identification method that uses cognitive mapping as a modeling device for eliciting and recording individuals' views of a problem situation. The merged cognitive maps provide the framework for workshop discussions, and a facilitator guides the group towards commitment to a portfolio of actions [Eden, Jones, and Sims 1983].

There are no "typical" applications of these methods. Nevertheless I will indicate here some accessible accounts of practical applications, which can provide guidance for those attempting to assess the costs and benefits of getting to know one or other of the PSMs in more detail. My edited collection [Rosenhead 1989] includes chapter-length accounts of case studies for each of six PSMs to complement the more theoretical expositions of scope, modeling formalism, and procedures. Other instructive case studies include the following: —Best, Parston, and Rosenhead [1986] describe an application of robustness analysis to planning health services for Ottawa and the surrounding region of Ontario. They used DELPHI and cluster analyses in conjunction to generate alternative possible futures. Extensive consultation with health care deliverers and with the public were other features of the study. —Checkland and Scholes [1990] provide the fullest description so far of SSM in action, with detailed case studies of work in

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—Strategic choice approach (SCA) is a plan-

ning approach centered on managing uncertainty in strategic situations. Facilitators assist participants to model the interconnectedness of decision areas. Interactive comparison of alternative decision schemes helps them to bring key uncertainties to the surface. On this basis, the group identifies priority areas for partial commitment and designs explorations and contingency plans [Friend and Hickling 1987]. —Strategic options development and analysis

PROBLE]VI STRUCTURING METHODS government agencies, major corporations, and other bodies. The most extended account concerns reshaping the internal organizational structure and processes of a division of a major transnational corporation. —Eden [1985] describes an application of SODA in the publishing industry to determine strategic directions for a group of magazines. The facilitator adapted the SODA procedures to involve members of the large management team in ways reflecting their distinctive potential contributions. —Howard [1992] discusses and compares three applications of metagame analysis: (1) to improve bidding success for an engineering firm, (2) to help a supplier of raw materials to increase margins by squeezing distributors, and (3) to develop strategy for government negotiations with industry representatives over reductions in air pollution. —Moulin [1991] helped women dissatisfied with health service provision to articulate their demands for better birthing facilities. He used the strategic choice approach to enable them to crystallize what they wanted. Their greater effectiveness enabled them to influence the services provided. Brief accounts like these cannot provide readers with a sense of how problem structuring methods operate in practice. To reduce this difficulty, I will give more extended accounts of two contrasting case studies. The first illustrates the potential of PSMs to work interactively to produce a well-defined project that can be addressed using a more traditional OR method. The second indicates their ability to clarify the

problem situation, so that participants can agree on action without "hard" analytic assistance. Developing Models to Support a Claim for Damages Analysts can employ SODA in a range of ways as a "front end" for analyses which are then conducted by more conventional methods. They can use SODA for the problem formulation stage, after which, for example, they may find the problem amenable to evaluation by multicriteria decision methods; or the process may focus attention on a key uncertainty that requires targeted market research. In a study reported by Williams et al. [1995], SODA was used in a more complex way in conjunction with system dynamics. A team from the University of Strathclyde carried out the work for the Canadianbased company Bombardier. Through a subsidiary. Bombardier had contracted to develop and supply the shuttle wagons to take cars and buses through the Channel Tunnel linking Britain and France by rail. The client was pursuing a legal claim against the tunnel's builders, Trans Manche Link, based on the delay and disruption it alleged had been caused to its activities by TML's introduction of revised specifications and by TML's delays in approving design documents. Revised specifications for a particular component may not only result directly in extra design time; they can also have extensive ramifications for other parts of the system. Delayed approvals can disrupt the design schedule, result in the need to work on designs in parallel rather than in series, and cause design work to be carried out in ignorance of the specification of related parts, leading


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ROSENHEAD to the need to redesign. The analytic problem was to develop models capable of quantifying the resulting delay and disruption, and capable of carrying conviction in court. The importance of feedback cycles in the problem situation made system dynamics (SD) a natural modeling language. However, the problem was very large (some 300 variables were eventually required), knowledge was distributed over the management team, and individual managers had different ideas about how the various factors interacted. The first use of SODA on the project was as a knowledge acquisition process; the academic consultants interviewed each member of the client team, and recorded his or her perceptions of relevant factors and cause-effect relationships

The consultant is a facilitator.

as the raw material for constructing an influence diagram as an intermediate stage toward constructing the SD model. The consultants generated the influence diagram by identifying and extracting the feedback loops (98 in all) embedded in the SODA model. Clustering those loops with shared components helped them to prioritize areas for analytic work—primarily the design stage and then secondarily the process engineering and manufacturing stages of the project. As the team moved from influence diagram to SD model, the SODA model remained in play as a knowledge repository for the study and as a medium of communication between analysts and clients. It was of particular value that, whereas an SD model represents only one view of the problem at a time, the SODA model could store and relate inconsistent perspectives. The views of corporate managers often differed from those of plant managers, while verbal reports conflicted with much of the hard data. As new inputs became available, they could be used in conjunction with the SODA model to reevaluate the validity of the viewpoints that had been incorporated in the SD model.

as a cognitive map. The Strathclyde team merged these maps into a group map, showing the network of ideas elicited. The client team, together with lawyers working on the claim, debated, corrected, and elaborated the structure of this group map at a series of workshop sessions, assisted by members of the Strathclyde team. This validated SODA model would form a continuing reference framework for the remainder of the study—as a reminder of the broader relevance of particular detailed analyses, as a means of identifying which aspects of the resulting SD model would need revision when new assumptions or data were introduced, and as a medium for explaining progress to those outside the project team. More immediately, it served

The resulting SD model was required to reproduce historically observed behavior (for example, the total number of freelance designers employed and their distribution over the lifetime of the project) with credible accuracy. It would then be used to emulate what would have happened if actions that were the subject of legal action had not taken place. The difference between pairs of runs would then form the basis of a costed claim for delay and disruption. In the event, the legal action was settled

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PROBLEM STRUCTURING METHODS out of court. Bombardier was clear that the evident power of the modeling approach used to support the claim for costs was influential in securing a very satisfactory settlement. Contesting Health Strategy in a Deprived Inner City Area

On an exploratory visit to meet representatives of the groups, we found that things had moved on. They saw an imminent threat that the district health authority (DHA) would close the accident and emergency unit at Mile Fnd Hospital. Mile End was effectively an outstation for the Royal London, a prestigious teaching hospital not far away. However, Mile End was viewed as a key health care resource for the local community. The general view was that closing Accident and Emergency (A&E) would prepare the way for the end of acute services and the eventual closure of the hospital. The groups' representatives agreed that this impending crisis must take priority as the focus of the planned strategic choice workshop, which should be convened with urgency.

Tower Hamlets is probably the most deprived borough in Greater London. It has absorbed successive waves of immigration, most recently from Bangladesh; much of the population, of whatever ethnic origin, is subject to vicious circles of disadvantage. As might sadly be expected of this sort of area, health services inadequate to the need are part of the problem. In September 1987,1 received an invitation (through a former student) to work with three local community health organizations to develop an external critique of the methodology used by the Tower Hamlets Health Authority to determine healthservice provision. I was quick to involve John Friend, principal developer of the strategic choice approach, which it seemed might be appropriate. Friend [1994] describes the resulting engagement. One of the three groups was the Tower Hamlets Community Health Council, a statutory agency responsible for representing the views of the local population on the health care it receives. The second organization was the Tower Hamlets Health Campaign, a group with a strong trade union involvement, which was active in defending the local health service from cuts. The third organization was the Tower Hamlets Health Strategy Group. Chaired by the local vicar, this free-standing organization aimed to channel local pressure for improvement in health services.

The workshop was held on October 15th, with 13 representatives of the three local organizations attending. Matters had already moved on again. The DHA was now due to confirm a management proposal to close the A&E Unit at a meeting scheduled for the following week. The strategic choice approach most commonly operates entirely in workshop format, as it did at the October 15th meeting. The participants, assisted by one or two facilitators, use the SCA framework to represent their understanding of their situation. Along the way they engage in, perhaps more than once, a shaping activity, in which they establish key areas for decision; a designing activity, in which the method helps them to identify feasible combinations of options for action in these areas; a comparing activity, in which they evaluate these alternatives against a range of criteria they see as important; and a choosing activity in


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ROSENHEAD which the method leads them towards agreement on commitments in some areas and exploratory investigations in others. There are decision aiding tools for each of these four modes. During the discussion in the shaping mode at the October 15th workshop, the participants identified seven key decision areas, and the pair-wise connections between them. One such area was possible alternative arrangements for A&E facilities in the borough, which in turn linked to the functions of other local hospitals. The future role of Mile End Hospital (the decision area of most urgent concern) was linked not only to the provision of A&E cover, but also to decision areas concerning the future of "community and priority services," and to care arrangements for mental illness and handicap. (These were two alternative uses for Mile End if it should cease to be an acute hospital.) Another decision area that emerged was a proposal, still at an early stage, to open a medical college in association with both Mile End Hospital (if it was still functioning as an acute hospital) and a nearby college of the University of London.

the full range of acute services, and reducing it to "cold acute" status by the closure of A&E. The implications of these two options were spelled out in more detail by adding in compatible options from other decision areas. The group started the process of comparing by listing a range of criteria on which these options should be evaluated. These were not only the group's own criteria but those they thought other parties would consider important. The group tried to identify where the balance of advantage between the two options lay on each of the key criteria: cost, management control.

Where no one can give orders, knowing an optimal solution is of little use.

Normally at a strategic choice workshop, participants agree to work with a problem focus of about three important, urgent, and interlinked decision areas. In view of the shortness of time—we had only four hours for the workshop—and the dominating threat of A&E closure, we agreed to take only one decision area as the problem focus: the future of Mile End Hospital. This was indeed "planning under pressure" [Friend and Hickling 1987]. The participants shortened the designing phase by agreeing to consider just two contrasting options for Mile End: maintaining

teaching, staff morale, and prestige. This process usefully threw up areas of disagreement or uncertainty—in particular the cost of continuing to duplicate services at two sites (Royal London and Mile End), the viability of cold acute operation, the costs that closure would generate elsewhere in the health system, and the state of the fabric of Mile End Hospital (and hence the costs of bringing it up to an acceptable standard). All of this information was available in diagrammatic form, on the flip charts on which we had been recording the problem structure as it emerged, for the final choosing phase. In view of the prevailing uncertainties, many of the possible actions that emerged from discussion were exploratory in nature, including the possibility of early discussions with the DHA. However, the most creative discussion focused on what

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PROBLEM STRUCTURING METHODS form of public reaction to the closure proposal the organizations should issue. Before the workshop, the organizations had been expecting defeat and thinking only in terms of standard responses to the threat of A&E closure—a letter to the local paper, a demonstration with placards outside the hospital. As a result of the morning's meeting, the group could see at least two added dimensions that gave its campaign a good chance of fighting off the closure threat. First, the DHA was seen as heavily influenced by the views of powerful consultants at the Royal London. However, the discussion had established that an important subset of these consultants was involved in the planned medical college, which depended on Mile End remaining in full operation. There was scope, therefore, to at least undercut the DHA's enthusiasm for closure.

range of recipients. The workshop ended in excellent spirits, with a commitment to further workshops to address longer-term issues. Two weeks later, at the first of these, the DHA had already conceded the case against early closure of the accident and emergency unit at Mile End Hospital. The DHA sent representatives to each of the subsequent workshops.


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Many factors in this account are unique to the particular case. However, it is typical of strategic choice engagements in certain respects: the ability to work with multiple organizations in contested areas, to socialize and purposefully organize knowledge previously fragmented among participants, and to generate decision outputs in the form of immediate commitments combined with explorations to reduce the more crucial uncertainties. Some Current Developments The second innovative element in the orI have presented the different PSMs as ganizations' response was sparked by the separate and distinctive entities, which nevinclusion of management control as a diertheless constitute a recognizable family of mension of evaluation. This had brought methods. The family resemblance is reinthe North East Thames Regional Health forced by the fact that these individual Authority (NETRHA) into the picture. (The PSMs can be (and have been) disassembled structure of the National Health Service in and their component phases used either 1987 gave regional health authorities very separately or hitched up to another of the considerable powers over the DHAs within methods. their regions.) Group members recalled that Many PSMs consist of a loosely articuthe DHA was in NETRHA's bad books for lated set of processes (part social, part techfailures of management control in the renical), which permits users considerable cent past. The group could therefore mount freedom to switch mode or recycle. They an argument that the proposed closure was therefore lend themselves to creative reasboth a consequence of poor managerial efsembly. Users may carry through only fectiveness by the DHA and a recipe for some stages of a method, or they may comcontinued inadequate managerial practices bine methods: for example, SODA and in the future. SSM, strategic choice and robustness, hypergames and SODA [Bennett and Cropper Several members went away directly to compose appropriately targeted letters to a 1990; Gains and Rosenhead 1993]. There is

ROSENHEAD also some limited evidence of work across the divide between hard and soft methods [Bryant 1988]. Experience reported from Shell International [Gibb 1993; Mapleston quoted in Holt 1993] suggests a potential for using particular aspects of a PSM without embracing the method in its entirety; using a PSM for only a part of the journey from problem appreciation to firm commitment; and using PSMs not for stand-alone projects but as elements embedded in larger projects.

tive responses by nature of the position or personality of their originators. Another positive argument for computer involvement is its potential, given the wide availability of PCs and the difficulty in convening full group meetings, to enable work to proceed wherever subsets of the project group can find time and space to gather. Evidently these issues place PSMs alongside group decision support systems [Finlay and Marples 1991] and computer supported cooperative work.

One shared feature of PSMs, which distinguishes them from OR's more conventional approaches, is the nature of the interaction between consultant and client group. In orthodox OR, the consultant is an analyst committed to extracting from perhaps recalcitrant data usable knowledge about the content of the problem confronting her clients. When operating with PSMs, the consultant is a facilitator, attempting to manage the complexities and uncertainties of problem content while simultaneously managing the interpersonal processes and dynamics of the client group. Facilitation is a specialized and demanding activity; if PSMs are to establish themselves in the OR repertoire, changes will be needed in the content of OR training [Eden and Radford 1990; Phillips and PhUlips 1993].

Future Prospects for Problem Structuring Methods

Almost all the major PSMs now incorporate purpose-built software, either as an optional or an indispensable element. Friend [1993] has expressed concern that introducing a computer into a workshop situation will adversely affect group dynamics. Conversely, Eden [1989] has suggested that the computer should be introduced precisely for its potential to depersonalize messages that might otherwise generate unproduc-

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It is reasonable to be sanguine about the future prospects for PSMs. They offer a route around the frustrating roadblock that has held operational research at a distance from many of society's more demanding problems. I see this problem of OR/MS's nonacceptance as the result of a failed attempt at inappropriate technology transfer. PSMs appear to provide a more appropriate model-based assistance than do conventional OR methods to problem specification and resolution in nonconsensual, multiparty predicaments. If so, they have the potential to open up the road to a constructive OR engagement with strategy. These are early days, and this statement deals with promise rather than fulfilment. However, we can reasonably expect further methodological innovations as this fast developing field multiplies its experience. The development of PSMs generated some imperialist proclamations from either side of the hard-soft divide. Both are equally misguided. Problem structuring methods can no more perform the tasks of conventional OR than the reverse. What PSMs provide is an extension of the OR

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PROBLEM STRUCTURING METHODS repertoire, rather than a driving out of former evil spirits. That said, I am persuaded, with Schon, that the wicked problems, the problems of the swamp, are of greater social significance than those relatively tame problems that OR to date has been technically and methodologically equipped to tackle. The problems of the high ground are tractable because they have many givens. It is through the processes in the swamp that these givens are established. The scope to influence social developments is thus far wider. Using model-based methods we can achieve a purchase on these situations—but only if we abandon any notion that their role is to replace subjectivity, that is, judgment, by analysis. Instead we need methods that interleave judgment and analysis, which aim to support judgment, not substitute for it. From many perspectives this liberatory aspect of PSMs (by contrast with the control paradigm of more orthodox approaches) is one of its principal attractions.

PSMs have proved themselves well adapted to a nonmanagerialist, nonhierarchical environment, where resource allocation is not an issue (because there are no resources) [Thunhurst et al. 1992; Thunhurst and Ritchie 1992]. There is also some evidence of their applicability to problems of development in third world countries [Bornstein and Rosenhead 1990; Rosenhead 1993]. Public policy making itself is perhaps the most significant area of potential applicability for problem structuring methods. In the 1970s, overenthusiastic advocates made such inflated claims for a high-tech version of policy analysis that it was discredited, and that left the field open to the dangerous form of hyper-irrationalism that now prevails worldwide in governmental circles [Rosenhead 1992]. Multiple advocacy, a necessary basis for sound policy analysis, is a process that could be well served by participative, multiple-perspective approaches of the kind that problem structuring methods can deploy. Achieving a more structured debate over policy formation would be a prize not just for operational research, but for the society we serve.

The elimination of the assumption of a singular rationality renders PSMs particularly appropriate in the public domain, in which much of the terrain is contestable. How successfully PSMs can be employed actively in public debate is, however, open to doubt. The small group dynamics through which PSMs operate can generate a high level of commitment among those who have shared the experience. However, the resulting conclusions do not necessarily cany conviction to a larger constituency. Contributions to debate may, therefore, be more indirect. One area of unconventional OR practice that has already made extensive use of PSMs is community operational research.

761-767. Bennett, P. G. and Cropper, S. A. 1986, "Helping


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