The project of KIWiS 2016 correctly highlighted that "The economic crisis and, consequently, the social crisis that hit most European cities is having effects on transformation and urban regeneration processes. More and more often we see cases of "large" projects abandoned, deferred or lapsed, either by difficulties encountered by operators for the exponential delay in approval times or realization or, as in most of the recent cases, for the coming up of unsustainability costs of realization. On the basis of recent experience, it appears that today this approach to urban planning, characterized by great works, long lead times and high costs, it is questioned and it appears, also, in crisis.

Urban regeneration is an emergency but requires more measured, rapid and widespread interventions and with low investment: recoveries, demolition and reconstruction, creation of public spaces. No more time for large projects projected over the long term and in need of substantial capital, it’s necessary to improve the quality of urban life with small actions, fast and flexible, low cost and low or no impact, in the places of everyday life; in the spaces of real life.”

If all this is true, and we think it is, then there is a clear need for aid in promoting a holistic approach to urban regeneration in which the culture of evaluation, in particular economic, and estimates plays the usual role of auxiliary tools for decisions: learning to decide by building a path of continuous references between rationality and invention.

In other words, really changing the reality around us to make it more fitting to our needs implies a decision-making process as a synthesis of formal solutions and their possible implications in terms of: capacity to satisfy the needs for which they were designed, resource requirements for their realization, and diachronic implications in terms of management and maintenance.

The decision-making process does not have a rectilinear course in which each successive pass is a necessary and an unambiguous consequence of the previous steps.

It is, rather, a directed branched system representable by a directed graph, where each node is connected to another downstream of an evaluation process implicitly or explicitly.

Decisions pertaining to the rethinking of urban spaces cannot be taken only through a process aimed at identifying the formal solutions most consistent with the world view of the designer, but also while taking into account the technological implications necessary for its technical feasibility.

The absence of control of estimative implications, under construction and management phases, is one of the main causes of the proliferation of unfinished or unused works.

Another aspect that appears to be significant is the legitimacy of decisions: why was a project chosen over another? Why was a given solution adopted?

The total de-legitimization of the political class, as well as the loss of sure cultural references produced by the collapse of ideologies, makes it difficult to build a consensus around the decisions of local public officials.

To make the objectives that a decision-making process intends to pursue and the criteria adopted explicit to choose among the conceivable alternatives, at least make clear the way in which it has reached a certain choice and, at the same way, make it possible to modify and to improve the choice through a rational path.

If all this is true for the individual public project, it is even truer in the context of a more intensive program of activities, as an urban renewal program of significant parts of the city.

In this case, on the considerations set out above, which retain their validity, additional levels of complexity add themselves to the decision-making process dictated by the need to take into account the presence of several actors, public and private, with the municipal administration that takes for direction, coordination and control.

How does it contribute to meeting the needs of the community to entities that differ from the local authority? How does it create conditions for private convenience? How does it make the collective conveniences contemporary with private ones possible?

Again, the culture of evaluation can support decision-making through estimating the impacts that can be generated from alternative hypotheses, verifying the persistence of convenience conditions for all parties, and ensuring the sustainability of the interventions.

The decision-making process at the time when the system of identity resources is involved becomes even more complex, where the expression of a judgment of convenience is entirely outside the logic of the market. However, there remains a need to ensure, through appropriate management models, the sustainability of the interventions in a historical period in which it is no longer possible to think about the use of public resources for the management.

Historically, the cost-benefit analysis from the earliest experiences of the 30s of the last century was made in the United States and then gradually in all subsequent areas. This intended to demonstrate that the benefits to a community, deriving from a particular work, outweighed the costs it had incurred.

This test was sufficient by itself to finance the work in a political-economic context, which considered the public debt as a useful tool to increase the collective welfare; it was still far from being the problem that severely affects the contemporary public policies in the Western world. In fact, it was operating as if there was an ideal position with unlimited resources.

The gradual decline in public spending has changed the paradigm of reference for the economic evaluation of projects: the decision-makers have to give answers to needs that are always unlimited but with fewer resources always available.

It is in this context, and also for other reasons omitted for brevity here, that for the use of public resources for urban and territorial transformations, new tools as Complex Urban Programs and Strategic Plans are designed.

The results of these new tools are not yet satisfactory but they make sense of their potential, thus stimulating the research for the necessary correction for their effective application.

In particular, the culture of evaluation can and should make a significant contribution to the improvement of these tools: it is clear, however, that paradigm shifts mentioned above also determine the need for a radical change in the assessment tools used.

Generally, a number of decision makers, each with his or her own objectives and priorities, govern the problems and the impacts of these targets are necessarily expressed in different units.

It is, therefore, one of the decision-making problems: multi-decision makers, multi-objective and multidimensional, in which the available information is represented by a matrix of mixed data with quantitative and qualitative values.

All evaluation problems are analysed by identifying and entering the information in the decision-making model

(Figure 1), the following elements:

Any problem to be solved makes use of decision support, i.e. evaluation techniques.

More recently have we developed decision support techniques such as multi-criteria analysis and multiobiettivio where it is not required to use a single unit of measurement but it is rather possible to compare quantitative and qualitative data.

One of the main implications of the multi-criteria approach was the renunciation of optimality paradigm in the new analysis techniques. With the presence of heterogeneous objectives often in conflict with each other, it is usually not possible to find solutions that simultaneously pursue all objectives and the decision problem is solved looking for the most satisfactory solution, or better "more coherent" with the logic of the decision makers.

The choice must therefore be affected within the set of non-dominated solutions; those solutions that realize a certain level of achievement of the various objectives such that it is not possible to improve the level of one of them without causing a worsening of the level of at least one other objective.

A multiobiettivi decision problem is thus solved by transforming it into a series of mono-objective optimization problems in which one of the objectives is chosen as a function to be optimized with respect to the target on the level of achievement of the other objectives.

In this valuation context, the Multiple-Criteria Decision Making (MCDM) methodologies, and the Analytic Hierarchy Process (AHP) in particular, play a significant role as they allow all the intrinsic values of the assets in question to be taken into account, both economic and extra-economic (Roy & Bouyssou, 1993). The use of these methods can provide choices that are not always based on the best cost-benefit ratio but, for example, which optimizes the quality of conservation or that safeguards the intrinsic value of the asset (Nesticò & Pipolo, 2015). As well as guaranteeing the presence and the clarification of different values, the formalisation of an evaluation process carried out in these terms, expression of the community needs, also allows the control and the correspondence between general and specific choices. Since the asset is of a particular value, it is, however, necessary that the various criteria and weights taken on the basis of the evaluation be shared by the community or rather, by direct users and by potential or future users.

The Analytic Hierarchy Process (AHP) among various MCDM provides a hierarchical analytical method that has found many applications in evaluation of priority and pre-feasibility of different projects. As techniques that help decision-making, the AHP has been, up until now, applied to an extensive variety of decision problems such as the selection of projects, planning public resources such as energy and medical resources and, more generally, conflict analysis and strategic planning (Calabrò & Spina, 2014). Specifically, the AHP, developed by Saaty, is used to achieve preference scales on the basis of the comparison pairwise technique between the elements that make up the decision problem in relation to a defined objective (Saaty, 1980). Users of the AHP first break down the decision problem into elementary parts and subsequently compare each pair of data in order to develop a priorities scale among the alternatives at each level of the decomposition.

Effective help to the study and support to the decision of those issues are offered through the multi-criteria analysis group (Figueira et al., 2005). Among them is the AHP methodology used as a tool that can provide an integrated approach to the issue of sustainability assessments.

The hierarchical scheme illustrated in Figure 2 is organized on two levels of criteria: the first is through the use of artistic, economic, social and cultural indicators trying to define the priority matrix in three different scenarios whilst the second level of criteria, through characteristic elements of the problem, addresses the construction of ”appreciation matrices” of the criterion in relation to the four alternatives.

The assumptions and criteria used in the evaluation process represent the synthesis of a comparison to make with Delphi-type procedures through the interaction of a panel of selected and independent individuals (experts, privileged witnesses, etc.). They anonymously interacted and actively debated the complex problem, thus creating an independent communication process (Okoli & Pawlowski, 2004). The communication among participants in the panel allows each expert to express their knowledge, perspective and opinion on the evaluation issue and reconsider, after feedback, the opinion expressed by others.

The aspects of the overall value of the property are thus identified: the fundamental coordinates against which to assess the possible works of transformation and reusing of the asset.

The Economic Value (E.V.) is expressed by the monetary benefits resulting from the asset or rather the benefits it should return (in terms of opportunity cost) (Calabrò & Spina, 2014).

The Cultural Value (C.V.) represents the "intrinsic value" of the asset, namely the incommensurable or qualitative values. It is expressed with the use of Multi-Criteria analysis.

The Social Value (S.V.) is expressed in order to gather all the benefits originated, in time and space, by the conservation using the division among the different types of users. The Social Value as an expression of the needs of the present, potential, and future community, which also reflects those ”post-materialistic” needs that manifest the need to conserve and protect its cultural and historical heritage. These three aspects (criteria) represent the fundamental coordinates with respect to that which must be placed on the issue of evaluation of a resource and, above all, the evaluation of possible projects for transforming it. In addition, they define the ”complex social value” of the resource, as a whole of all the benefits (economic, cultural and social) that can be achieved over time from the asset by all users (direct, indirect, potential and future).

The multi-criteria methodologies have proven particularly useful in the process of urban regeneration and local development. It is an instrument of mediation among the multiple and often divergent interests and is able to create a shared platform among all decision-makers, stakeholders and people directly affected by the final solutions. The use of different techniques of MCDM in the preliminary stages will support public administration in complex decision-making problems ensuring that they are integrated, multidisciplinary and transparent in the whole evaluation process. It has emerged that these tools are extremely strategic, especially if adopted early in the planning stage or the pre-feasibility, playing a role of control and management (Cassalia, 2014). It can support the public body in the choice among different policy options through negotiation among the various stakeholders for a more transparent and efficient identification of shared and sustainable choices [(Calabrò & Spina, 2014); (Spina et al., 2015)].

Thinking in terms of sustainability, the MCDM plays an important role in the path towards sustainability. To consider the development for sustainability means considering the multiple dimensions involved in the development and planning of the urban transformation (D’Alpaos, 2012), considering the development as the result on the short and long terms, interconnected social, economic, and environmental objectives (Calabrò & Spina, 2013). For this purpose, the MCDM and in particular the AHP lends itself as a tool capable of dealing with this multidimensionality in an integrated way and reflects the complex interdependencies among the different dimensions of the transformation and reuse of the asset. The high transparency of the AHP steps and simple hierarchical representation of the various evaluation stages are the widespread application of this multi-criteria technique and its intrinsic effectiveness in identifying shared choices. The use of the hierarchical diagram, the matrix of the criteria, and the matrices of the alternatives being input and the vectors of preferences for the different scenarios in the output stage characterise the multi-criteria technique of operational simplicity and clarity of the mathematical process, making it logical for everyone involved.