**3. Discourses as networks**

courses. Heterogeneous actors contribute to different problem definitions, and dominant or

Another facet of discourse arenas is their limited *carrying capacity*: only few problems can be addressed at once [39]. While the respective subsystems specialize on a given issue, in most cases a bunch of issues compete for attention. Their competitiveness depends on *novelty* and *dramatic value*. According to Downs [40], public attention follows a cyclical pattern of rise and decline. Such issue cycles have been extensively discussed in the literature, wherein two points have been emphasized: firstly, major external events catalyze issue attention because they create a sense of dramatic crisis that cannot be sustained in their absence [41, 42]. Sec‐ ondly, claims-making activities alone cannot explain that one issue attracts more public at‐ tention than another [43], but they play an important role in connecting a specific event to

This study distinguishes four stages of collective problem redefinition within public dis‐

*Entry and exit.* Individual and corporate actors (just like the discourse arena) have limited carrying capacities. Because of limitations in time, budget and personnel, they can only process few issues at a time [39]. When there is extensive media coverage of an issue, some actors that were not interested in the issue prior to a media hype now become engaged in public discourse either because they realize the problem's importance or because they use it

*Framing*. Problem definitions depend on framing, which is "*a way of selecting, organizing, in‐ terpreting, and making sense of a complex reality to provide guideposts for knowing, analyzing, per‐ suading and acting*" [46]. Frames enable actors to get some understanding of complex situations and facilitate communication and action with regard to a perceived problem. The way an issue is framed impacts on whether people notice a problem, how they understand it and what viable solution they take into consideration. The framing of an issue is not neces‐ sarily constant – neither the individual nor the collective way of framing. Actors aim to get

*Salience.* This concept describes how much a frame dominates the discourse [47]. A frame has a low salience if it is used rarely by few actors whereas its salience is high if it is used repeatedly by many actors. When attention to an issue rises or declines, shifts in actor con‐ stellations also generate changes in frame constellations. New actors contribute to new frames while old frames vanish when their supportive actors leave the discourse arena [45]. *Proposal and debate.* Changes in the collective framing of an issue also changes influence de‐ bates on policy measures. Based on the multiple stream approach, proponents of PE theory expect that political actors are sometimes more interested in making sure that "their" policy solutions are adopted than in what problem these solutions address [45, 48]. During phases of collective problem redefinition policy entrepreneurs promote their policy ideas as solu‐ tions for the problem under discussion. As these ideas do not derive rationally from prob‐ lem perceptions, they are nevertheless expected to be compatible with different problem

consensual policy images are established only by way of tedious debates.

the definition of a policy problem [44].

162 Environmental Change and Sustainability

as an occasion for self-promotion or other policy strategies.

their frame recognized as the authoritative version of "reality" [36].

course [45]:

interpretations.

In this study we use a formal and quantitative approach to discourse analysis. As ex‐ posed in the previous section, discourses consist of sets of individuals and organizational actors, groups of actors, and sets of concepts such as frames or positions. All of these re‐ fer to issues under discussion and emergent relations in terms of communication. Con‐ cepts do not float freely in the air or "hover above society" but are instead attached to concrete actors that use them within discourses to persuade others of their own problem interpretation. Discourse coalitions emerge among actors that are connected by similar is‐ sue positions and policy frames. Specific frames and problem definitions must not be mutually exclusive but differ with respect to their reconcilability [25]. This study as‐ sumes that the same actor is able to consider a problem from different perspectives and to use different frames within a given discourse. An actor might do so out of conviction or with strategic motives. In any case, two concepts that are used by the same actor in the same way (in the case of positions, the actor supports both or opposes both posi‐ tions) can be assumed to be reconcilable to a certain extent.

Discourse network analysis formalizes these multiple relations by means of graph theory: A graph *G* consists of nodes from the set of actors *A={a1, a2,a3...am}* and/or from the set of con‐ cepts *C={c1, c2,c3...cn}* and edges from the set of interrelations between nodes *E={e1, e2, e3...el}* (Figure 1). Based on these formal concepts several types of graphs can be created:


These networks can be analyzed by conventional tools of social network analysis. This study is interested in the standing of actors as well as in the salience of concepts. Stand‐ ing designates an actor's visibility in terms of how much he/she contributes to the public discourse. An actor's standing depends not only on his/her commitment but also on whether he/she succeeds in positioning his/her problem interpretation within the media arena. In terms of network analysis, standing designates the actor's centrality within the discourse. Salience designates how much a concept is incorporated in a collective prob‐ lem definition, how often it is used and how central it is within the affiliation network. Issue coalitions, groups of actors that share similar policy ideas are subgroups within the actor network in terms of network analysis. The reconcilability of issues is reflected by their interconnectedness within the issue network.

#### **Figure 1.** Discourses as Networks (Source: (6))

The sets of actors, concepts and edges change over time as actors enter or leave the dis‐ course and change their respective problem interpretations. When one actor leaves the discourse, this reduces not only the set of actors but also the set of edges a) within the actor network by those edges that previously connected this actor to other actors, b) within the affiliation network by those edges that connected this actor to concepts, and c) within the concept network by those edges that connected the different concepts which had been used by this actor. When an actor leaves the discourse, that used to ap‐ ply many different frames and to comment several policy measures, significant structural changes can be observed in all networks
