Organizational structure and responsibility

2.1 Organizational structure and organizational activities

Organizational structures are sets of relations between the roles of an organization. A typical abstract example of such structures is the so-called “vertical differentiation” or “authority structure” of organizations, usually considered to be a “hierarchy” structure. These abstract types of structures are traditionally studied in the branch of sociology known as mathematical sociology (Fararo 1997; Sørensen 1978).

Work on organizations (especially in MAS ¹) presents organizational structure as something essentially mono-dimensional, though it often, but only implicitly, considers a multiplicity of structured aspects: authority, communication, delegation, responsibility, control, power, etc. The thesis we hold here, which is inspired by foundational work on social and organization theory like Selznick (1948), Morgenstern (1951) and Giddens (1984), is that organizations do not exhibit one single structural dimension, but that they are instead multi-structured objects. In particular, we view organizational structure as hiding at least three relevant dimensions which we call: power, coordination and control.

These different structural dimensions are linked with as many specific activities that take place within any organized group of agents acting to pursue some goals. These activities, which we call organizational activities, consists in “managing the interdependencies between the activities” (Decker and Lesser 1995) of the group. In other words they guarantee the group ‘to act in an organized way’. We will analyze three of these activities: delegation, information and monitor, each of them related with one specific structural dimension. The delegation activity, concerning the flow of obligations within an organization is related with the structural dimension of power. The information activity, concerning instead the flow of knowledge within the group of agents, is related with the coordination dimension. Finally, the monitoring activity, concerning the recovery functionalities of the organization, is related with the control dimension.

As a result of this analysis, organizations will be represented as explicitly displaying a triple structure constrained on the basis of the interplay between the three notions of power, coordination, and control (see Definition 3.1). Although we do not pretend to give full definitions of these relations, we will characterize these relations in terms of the consequences they bear for the performance of organizational activities. In a nutshell, our thesis is that organizational structure makes organizational activities possible, that is, what organizational structure does is to make it possible for a group of agents to act as an organization (see Sect. 4.1).

In fact, delegation concerns the redistribution of tasks within an organization. To realize their objective organizations needs to attribute tasks to agents according to specific plans for the realization of those objectives (see Sect. 4.4). Delegation introduces a dynamic within this attribution of tasks transferring tasks from agents to agents when the recipient of the transfer plays a somehow subordinated role within the organization. The transfer takes place in the form of a directed obligation (Dignum 1999) of the agent enacting the first role to the agent enacting the subordinated one. This second agent is thus obliged to perform a task which belonged to the first agent. The possibility of delegating goals constitutes one of the essential aspects of organizations. The power structure concerns exactly the channels through which this task flow can take place: “who can (successfully) delegate to whom?”

The coordination structure should then guarantee that each agent has a representation of the actual state of the organization which is sufficient for it to accomplish its tasks. The question is then how the access and sharing of information is structured within the organization: who can (successfully) inform whom?

Objectives and norms also determine to a great extent the control structure. Since agents’ tasks can be accomplished or not, the monitoring activity is an indispensable activity in which any organization has to engage. This is the case also for MAS organizations where agents, even if “benevolent”, are anyway subjected to the possibility of failure. In its simplest form, control consists in a monitoring activity triggering appropriate reactions to determinate failures or violations. If an agent fails in performing one of the stated or delegated tasks, a kind of supervisor agent should engage in the performance of that task: organization calls for a form of supervision activity (Giddens 1984). Because of this, control can be seen as “an organization within an organization” (Morgenstern 1951). With respect to the control issue the relevant structural question is: who can (successfully) monitor whom?

Besides the activities of delegation, information and control, and their correlated organizational structures, a range of yet more activities can be isolated which play a crucial role within organized agency. One of them concerns the distribution of the necessary capabilities within the organization for agents to perform the required tasks. Such issue is somehow analogous to the information issue since it concerns requirements each tasks presupposes in order to be accomplished. A basic type of capabilities lies in the amount of resources that agents should have at their disposal. A second kind of capabilities plays a central role in organizations, namely those concerning the so-called institutional power (Jones and Sergot 1996; Castelfranchi 2003). Again the problem is related with the dynamics introduced by the delegation activity: delegating a task may require a parallel enabling or empowering activity such as making the relevant resources accessible, e.g., electronic money, and providing the required form of institutional empowerment, e.g., a suitable document. In this case the relevant structural question is: who can (successfully) enable or empower whom? We choose however not to complicate matters further and we assume in this work that all agents have the capabilities needed to perform the tasks they are appointed to.

2.2 Notions of responsibility: a sketch

The analysis of organizational structures concerns organizations at their role level. Responsibilities, instead, concern agents and arise in relation with task-allocation and structure once there are agents enacting the roles of a given organization.

Given a task-allocation allocating a specific subtask to a role, and given that an agent is enacting that role, the agent is then said to be responsible for that task or task-based responsible. In other words, the allocation of subtasks to roles determines a distribution of what we call task-based responsibilities over the set of agents enacting the roles of the organization. Task-based responsibilities can also arise via delegation under a power link or of a monitoring action under a control link. Thanks to a power structure an agent can appoint a new task to a subordinated agent and because of a control structure a monitoring agent can happen to be appointed to a task whose accomplishment failed.

Being autonomous, agents can independently decide whether to perform the subtasks to which they are appointed or not, and whether to perform them in the expected way. In this case the fulfillment of the organizational objectives is put in jeopardy by the conduct of some agent that is said then to be causally responsible for the failure occurred.

In organizations an agent can happen to be causally responsible of some failure without actually being accountable for that in the eyes of the organization. This can happen if an agent which is task-based responsible for performing a task, delegates the performance to a subordinate agent which fails to execute the delegated task. The second agent is causally responsible for the failure but it is the delegating agent that will be held accountable for the failure since it was the one appointed to the task in the first place.

The notion of accountability eminently reveals an interplay between the notions of responsibility isolated above, and dimensions of social structure such as the possibility to delegate allocated tasks, i.e., what we called power relation in the previous section. The presence of a power structure within an organization causes a difference between the two notions of task-based and causal responsibility: ‘I may have not performed the task you delegated to me, but you were the one appointed to it’. However, this is not the only case in which a given organizational bears consequences for the assessment of responsibilities within a group. As we have seen in the previous section organizational structure influences also the flow of knowledge within an organization and knowledge is an essential ingredient of yet another way of “being responsible” for something, namely, blameworthiness. An agent can be causally responsible for a failure without actually being blameworthy for that. This is the case, for instance, if it just was not informed about the task it was supposed to perform. The acknowledgment of such a gap calls for the distinction of yet another meaning of the notion of responsibility which we call blameworthiness.

All the informal notions of responsibility just sketched are formalized in Sect. 5.

3.1 Language \({\mathcal{L}}^{ORG}\)

The alphabet of \({\mathcal{L}}^{ORG}\) consists first of all of a set of agent identifiers Ag (groups of agents identifiers are denoted by \(X, Y, \ldots\)), and a set AR of roles identifiers. The set P of propositional symbols (p) of \({\mathcal{L}}^{ORG}\) contains at least the propositional constant V (violation) and all organizational structure propositions, that is, for any \(r,s \in AR\) and \(i \in Ag\): Power(r, s) (there exists a power-link between r and s), Coord(r, s) (there exists a coordination-link between r and s), Control(r, s) (there exists a control-link between r and s) and rea(i, r) (the agent denoted by i enacts the role denoted by r). Besides, \({\mathcal{L}}^{ORG}\) contains a set \({\mathcal{A}}\) of atomic action symbols typically denoted by \(\underline{a}\),⁴ the family of epistemic operators \(\{K_i \}_{i \in Ag}\) (“agent i knows that ...”), the dynamic operator [ ] (“after each execution of ... it holds that”), the LTL (linear time temporal logic) operators @_start (“it holds at the initial state of the run”), @₋₁ (“it holds at the previous state of the run”) and @₊₁ (“it holds at the next state of the run”) and the operator DO denoting what event is going to happen next. The set \({\mathcal{A}}\) of atomic actions contains at least the “do nothing” action expression skip and all organizational action expressions, that is: \(delegate(i,\alpha)\) (delegating action α to agent i), \(inform(i,\phi)\) (informing agent i that \(\phi\) is the case), \(monitor(i,\alpha)\) (monitoring the execution of action α by agent i) with \(i \in Ag\), \(\phi \in {\mathcal{L}}^{ORG}\) and \(\alpha \in {\mathcal{A}}\).

The language \({\mathcal{L}}\) is based on three types of syntactic constructs that we are now going to define.

A subset of Evt is of particular interest for our purposes, that is the set of events of the form \(X\;:\;\alpha\) such that X is a singleton and α is an organizational action in \({\mathcal{A}}\). We call this set of events OrgEvt, i.e., organizational events.

3.2 Models

With \({\mathcal{L}}^{ORG}\) we want to be able to talk about a number of different notions and in particular: organizational structures, hypothetical performances of actions by agents (i.e., events and their combinations in plans) and actual performances of actions by agents resulting in a run of the agent system. Our models should thus be rich enough to give a precise semantics to all these ingredients.

To model organizational structures we make use of the theory of directed graphs. However, we introduce only some basic elements of it which are strictly of use for the development of the article.⁵

The notion of organizational structure is an essential ingredient of the models for \({\mathcal{L}}^{ORG}\). They are defined as follows.

Like in Meyer (1988) and Dignum et al. (1996) our semantics consists of two parts: first event expressions are interpreted as set theoretic constructs on \({\mathbb{A}}\) where events get a so-called open interpretation; successively event expressions are interpreted as state-transition functions determining the accessibility relation \([\![\;]\!]_{R}\) on \({\mathbb{W}}\).

3.3 Synchronicity sets, steps, synchronicity traces, and worlds

The interpretation of events is based on the basic notion of synchronicity set (s-set).

Synchronicity sets, that is elements of \({\mathcal{S}}\), are denoted by \(S_{1}, S_{2}, \ldots\). Informally, a s-set is nothing but a set of parallel executions of events by a group of agents, and formalizes the aforementioned open interpretation view on events. We will often refer to s-sets by making the group of agents explicit in an index (e.g. S _X ). Based on the notion of s-set we define the notion of step.⁶

Steps represent a sort of snapshot of the activity of each subgroup of Agents at a certain moment, depicting how all agents move one “step" ahead. Steps are therefore sets of s-sets of cardinality 2 ⁿ −1 where n is the number of agents in Agents. They are constrained in such a way that whatever action is performed by a subgroup is also performed by a supergroup, and subgroups remaining inactive are treated as performing a skip action. Steps, that is elements of Step, are denoted by \(st_{1}, st_{2}, \ldots\).

In order to provide a semantics for sequential expressions the concept of synchronicity trace (s-trace) is needed. Notice that this concept uses steps instead of s-sets like it was originally defined in Meyer (1988).

An event will be interpreted as a set of s-traces. The range for our interpretation of events is a set \({\mathcal{E}}\) such that \({\mathcal{E}} = {\mathcal{P}}({\mathcal{T}})\). Elements of \({\mathcal{E}}\) (sets of s-traces) are denoted as \(T_{1}, T_{2}, \ldots\). The length dur(T) of a set T is defined as \(max \{dur(t) | t \in T \}\).

We can now introduce the operations that constitute the semantic counterpart of our syntactic operators.

Intuitively, we want \(\doublecup\) to yield the property: \(a \equiv a+a;b\) for event expressions. In order to establish this property we cannot just use a union of the sets of s-traces representing a and a;b but have to do some “cleaning up" by subtracting superfluous parts.

The semantics of events are obtained by means of a function \([\![\;]\!] : Evt \longrightarrow {\mathcal{E}}\) such that:

The basic clause stipulates that the meaning of an atomic event consists of the set of steps where that action at least is performed by that specific group of agents.

On the basis of this evaluation for events, an evaluation of groups performing complex actions is obtained:

To connect this interpretation of events to a possible world semantics a function \(R: {\mathcal{E}} \times \mathbb{W} \longrightarrow \mathbb{W}\) is defined, which couples events with state-transitions.

3.4 Evaluating formulae

The meaning of formulae \(\phi\) in a world w, given the structure M, is defined as usual. We report here only the clauses for the organizational structure propositions, the epistemic, dynamic and temporal operators, and the DO operator.

Informally rea assertions are an isomorphic representation within the language of the Rea relation in OS. The same holds for Power, Coord and Control assertions. As to the dynamic operator, a sentence \([ \xi ] \phi\) is true in w iff \(\phi\) is true in every world accessible through a performance of ξ. The semantics of \(@_{\rm {start}}\), \(@_{-1}\) and \(@_{+1}\) is quite simple and it is just based on the \( \prec \) path contained in M. As to the semantics of DO(ξ), the two clauses should be read as a basis and an induction step: intuitively, a sentence DO(ξ) is evaluated as true in a world w ₁ iff state w ₂ in the run can be reached via the sequence ξ of events. Notice that a backward looking operator DONE, denoting what event took place in order to reach the present state, can be defined as follows: \(DONE(\xi) := @_{-1} DO (\xi)\). In what follows we will thus sometimes use DONE-expressions as abbreviations for \(@_{-1} DO (\xi)\).

3.5 Deontic notions

Essential for our purposes is the possibility to express a notion of obligation, in particular of obligation for a group of agents to execute a given plan. We express deontic notions making use of a reduction strategy in the classical fashion of Meyer (1988).

4.1 Semantics of organizational actions

In Sect. 2 we have informally touched upon a number of activities that typically take place within an organized group of agents: delegation, information, monitor. In what follows we give a formal semantics of these activities, aiming at capturing some of their essential features. We do not consider our analysis, however, to exhaust all the aspects involved in the notions of delegation, control and monitor within organizations. Our aim is rather to capture those aspects that look more relevant in relation with the notions of responsibility which have been introduced in Sect. 2 and which are formally investigated in Sect. 5.

Essentially, the semantics we propose formalizes the connection between the organizational structures of power, coordination and control and the organizational activities of delegation, information and monitor. The existence of structural links between roles guarantees the successful performance of those organizational actions. In other words, in order for a group of agents to act in an organized way, that is, to be able to manage their collective endeavors, specific structures between the roles are necessary in order to guarantee the effectiveness of organizational activities.

If a power relation holds between roles r and s, all delegation acts performed by an agent a enacting role r on agents enacting role s succeed in creating an obligation for these agents. Analogously, if a coordination relation holds between roles r and s, all information acts performed by agents enacting role r to agents enacting role s are successful in the sense that they create knowledge in these agents. Finally, if a control relation holds between roles r and s, all monitoring acts performed by agents enacting role r on agents enacting role s do not only create knowledge in the controller about the relevant state of affairs, but they also determine an obligation for the controller in case the controlled agent did not perform the action that is monitored.

Intuitively, if a power relation exists between roles that are enacted by two agents and the delegating agent about knows the to-be-delegated obligation, then a delegate action has as effect an obligation for the recipient. A delegate action implements therefore, given an appropriate power link, a form of “your wish is my command” principle.

More technically, the definition states that, provided that the preconditions in the first clause hold, the set of state-transitions generated by a step st where event \(a: delegate(b,\alpha)\) is performed, is the subset of the state-transitions generated by the step st′ where no \(a: delegate(b,\alpha)\) takes place in which all transitions end up satisfying O(b: α). In other words what delegate actions do, with respect to all the other actions being performed in the step, is just creating obligations, given that the necessary preconditions hold. If the preconditions do not hold, then it is as if the action was never performed (this is the intuitive meaning of the “otherwise” clause).

Intuitively, if there exists a coordination link between the role enacted by the informing agent and the role enacted by the recipient, and provided that the informing agents knows that the to-be-communicated content is going to be the case in the next state reached by the system \((K_a @_{+1}\phi)\), then an inform action always results in the creation of the corresponding epistemic state in the recipient. A coordination relation enables thus agents with reliable and trustworthy information channels. Typical to-be-communicated contents are obligations to perform some action in the next state, or information about actions just undertaken.

In analogy with the definition of delegation it is stated that, provided that the preconditions in the first clause hold, the set of state-transitions generated by a step st where event \(a: inform(b,\phi)\) is performed, is the subset of the state-transitions generated by the step st′ where no \(a: inform(b,\phi)\) takes place in which all transitions end up satisfying \(K_b \phi\).

Looking at the definition from a more technical point of view, we see again the same patterns used in Definitions 4.1 and 4.2. If the preconditions in the first clause hold true, then the set of state-transitions generated by a step s where event \(a: monitor(b,\alpha)\) is performed, is the subset of the state-transitions generated by the step s′ where no \(a: monitor(b,\alpha)\) takes place in which all transitions end up satisfying \(K_a DONE(b:\phi)\). If the preconditions in the second clause hold true, then the set of transitions leads to worlds all satisfying \(\models K_a DONE(b: \overline{\alpha}) \wedge K_b O_b \alpha\). If none of the preconditions hold, the monitor action does not influence the transition generated by the step.

4.2 Organizational actions and knowledge

We consider organizational actions to be such that their necessary effects are always known to the agents performing them. In other words, the actions of delegating, informing, and monitoring, once executed by an agent, always determine the knowledge about their necessary effects which the agent expects. To use the terminology of Meyer and Van der Hoek (1995), these actions are always accordant to plan.

Intuitively, the constraint guarantees that any world reachable via a concatenation of the transitions of step st and \({\mathcal{K}}_i\), is also reachable via a concatenation of \({\mathcal{K}}_i\) and the transitions generated by s. It can be proven (see Meyer and Van der Hoek 1995) that such constraint validates Formulae 12, 13 and 14 in Table 2.

4.3 Organizational actions, knowledge, and deontics

Organizational actions are activities by means of which any collective agency can be managed. As we have seen they are dependent on the organizational structure of a group. When an agent, given a role-based plan and an enactment configuration, is appointed to perform a certain organizational action we consider reasonable to assume that it also knows about this appointment. In fact, we consider such knowledge to follow from the role enactment itself: if an agent enacts a role it acquires knowledge about its tasks. This motivates the following semantic constraint.

The constraint states that if all the worlds reachable via st satisfy the violation constant, then the same worlds are reachable via a concatenation of \({\mathcal{K}}_i\) and transitions generated by s. It is easy to see that such a constraint makes Formulae 15, 16 and 17 in Table 2 valid.

4.4 Role-based and agent-based plans

Organizations “represent rationally ordered instruments for the achievement of stated goals” (Selznick 1948), that is, organizations arise in order to achieve specific objectives, and these objectives are pursued defining a number of subgoals contributing to the overall purpose of the organization. These subgoals identify the roles that are played in the organization. The relation between subgoals and overall objectives of the organization, i.e., the primitive decomposition of tasks within the organization, defines the essential form of organizational structure: “viewed in this light, formal organization is the structural expression of rational action” (Selznick 1948). Roles are the basic units over which this structure ranges determining the source of the “rational order” holding in the organization. The above quotes consider then the decomposition of tasks as the central source of structure within organizations: structure is necessary for each organization to pursue its objectives.

In order for the objectives of an organization to be realized the organization needs to “translate” them in concrete sub-goals to be systematically reached following specific plans, i.e., via complex collective actions which, once performed, guarantee the achievement of those objectives. Normally, this “translation” of objectives into plans is described via the two steps of task division and task allocation.

Given a role-based plan and a role-enactment configuration a corresponding agent-based plan can be obtained which specifies which agent of the organization has to play which role in the plan. In other words a role-based plan \(Plan(AR, \tau)\) and a role enactment configuration Rea univocally determine an agent-based plan, i.e., a complex event description.

The definition makes explicit the translation step of the organizations’ objective into concrete plans for groups of agents: from an organizational level (roles) to a collective agency level (agents). Complex event expressions can be seen as the result of an instantiation process of role-based plans via role enactment configurations.

4.5 Plans and structure

In the previous section we distinguished between raw plans, i.e., complex action descriptions not including any organizational action, and proper plans, i.e., complex action descriptions which include instead organizational actions. The step from raw plans to proper plans is the most typical feature of planning a collective activity with respect to planning an individual one. When a plan concerns only the performance of a single agent, organizational activities such as delegating, informing and monitoring loose their meaning since those activities just happens within the single mind of one individual agent. Groups have, instead, no single mind even though they can act as if they had one precisely by undertaking appropriate organizational activities. Given a raw plan, an organization always needs to elaborate a corresponding proper plan which can accordingly manage the knowledge flow and the control issue within the group.

5.1 Causal responsibility

An agent a _i is said to be causally responsible for a state of affairs \(\phi\) by performing α iff it performs an action α whose necessary effect is the state of affairs \(\phi\) and it is not the case that if it did not perform α then \(\phi\) was anyway the case.

A particularly relevant case of causal responsibility is the causal responsibility for a violation. Such a notion is formalized by expressions of the form \({\mathfrak{CausalR}}(a_i, V, \alpha)\).

5.2 Blameworthiness

An agent which is causally responsible, may not be considered blameworthy. For example, if the chairman of the Editorial Board has forgotten to inform a member a _i to review some papers in one week, and agent a _i did not review the papers in one week, then the achievement of the goal of the Editorial Board to notify of the results of the reviews within the deadline will not be met. The agent would be considered causally responsible, but it would not be considered blameworthy. An agent does something causally blameworthy, if it is causally responsible and if it knows that the action it performs leads to a violation which could be avoided by not performing the action.

That is to say, a _i is blameworthy iff it is causally responsible of V and it knew in the very previous state of the run that the performance of α would have resulted in the occurrence of V.

5.3 Task-based responsibility

The notion of task-based responsibility corresponds to the notion of duty and refers to what the individuals of the organization are expected to do in virtue of their roles. As proposed also in Conte and Paolucci (2004), we assume task-based responsibility to be a consequence of role enactment. As we have seen, a role-based plan together with an enactment configuration univocally determines an agent-based plan. An agent who accepts to play a given role in an organization takes a responsibility with regard to the accomplishment of that role, i.e., with the tasks associated to it Conte and Paolucci (2004).

In other words, an agent is task-based responsible for the performance of a given action iff the event \(a_i: \alpha_i\) is part of the to-be-executed agent-based plan.

Definition 5.3 has interesting consequences concerning the relation between the notion of obligation and of task-based responsibility itself which can all be expressed in our language. First of all, task-based responsibility occurs in the very moment (situation, possible world) in which an obligation to execute a plan occurs which contains the relevant event (Formula 21). Besides, notice that task-based responsibility holds true at every execution stage of a plan (Formula 22) at least until the relevant event is performed for the last time (Formula 23).

Formulae 21 and 23 deserve in particular some more words. It is worth noticing why Definition 5.3 guarantees the persistence of the responsibility through the execution of the plan. That depends on the fact that after each execution of a fragment of the plan a new obligation with respect to the rest of the plan holds (see Formula 7). And as far as these new obligations hold for plans which include the event concerning the task-based responsibility, that responsibility also holds. As soon as the event is performed, persistence is not guaranteed any more. As a matter of fact, it would be desirable to have a stronger version of Formula 23 such as \(O(Plan(Ag,\tau)) \rightarrow [a_1: \alpha_1 ; \ldots ; a_{i}: \alpha_{i}] \neg {\mathfrak{TaskR}}(a_i,\alpha_i))\). However, this last version is not a validity since we cannot rule out the possibility of violation constants holding also in those worlds reached via correct executions of the plan. Obligations just state that if certain actions are not performed, a violation necessarily occurs (Definition 3.11), but they do not exclude that violations can hold no matter what actions are performed.

5.4 Accountability

The notion of accountability concerns the interplay of causal and task-based responsibilities. We say that an agent is accountable for a violation if it caused the violation by performing an action α and if it was appointed to \(\overline{\alpha}\) according to the plan that had to be executed at the beginning of the run. This notion is necessary because of the organizational actions of delegation and monitor which can lead to the generation of new tasks throughout a run of the system which are different from the one attributed by the original plan at the beginning of the run. In other words, the original task allocation established at the beginning of the run of the system is the one used for assessing accountability. These considerations are captured in the following definition.

It might be interesting to spend a few words about the intuitive meanings of the two expressions \({\mathfrak{TaskR}}(a_i,\alpha)\) and \(@_{\rm start}{\mathfrak{TaskR}}(a_i,\alpha)\). The first formula can be read as “agent a _i will have sooner or later to perform α”. The second formula captures the idea of an initial appointment of a task: “agent a _i has been appointed, according to the initial plan, to the performance of α”. Notice that neither the first implies the second nor the second implies the first. They formalize logically unrelated notions. In fact, I can have a task even if I was not appointed to it by the initial plan, for instance because I have been addressee of a delegation action. On the other hand, if I was appointed to a task this does not imply that I have that task at the current state, because I have for instance already performed the required action.

5.5 Responsibilities and organizational structure

In this section we show how our analysis provides a way for understanding the influence of organizational structure on the various notions of responsibility formalized in the previous section.

First of all we show a quite obvious result, namely that the existence of a power structure can determine the occurrence of a causal responsibility if the addressee of a delegation act does not perform the required action. This is no surprise since we know (Definition 4.1) that the existence of a power structure determines the successful creation of directed obligations via delegation.

On the other hand a power structure is not enough for determining accountability. In fact, accountability depends on the initial task-allocation assumed by the organization and it is not influenced by the creation of new obligations which do not stem from that task-allocation.

The following proposition shows that the occurrence of blameworthiness requires the existence of a coordination structure, which is instead not relevant for the occurrence of causal responsibility.

Formula 27 deserves in particular some more words. We see that in order to obtain blameworthiness the same condition determining causal responsibility is first of all required (first conjunct of the antecedent). The second conjunct of the antecedent states something about two steps backward in the run (@₋₁@₋₁). In that state an appropriate coordination configuration needs to be in place, and the informing agent should know that in the next state (i.e., one state backward in the run from the evaluation state) an obligation holds for the recipient of the information action. This complex statement is, thanks to the semantics of the information actions (Definition 4.2), guarantees that the recipient knows it is obliged and it therefore determines the necessary conditions for blameworthiness.

Finally we show that the control structure can determine the occurrence of new task-based responsibilities. If an agent is found to be causally responsible for a violation by not performing β, then if an appropriate control structure is in place and a monitor action is performed to check whether β has been performed then the monitoring agent becomes task-based responsible for that action.

Other results of this kind are obtainable in the framework. Our aim in this section was to provide a satisfactory sample of some intuitive relations among the concepts of responsibility and organizational structure which find a natural formalization in the framework.