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Party Competition: An Agent-Based Model

Party Competition: An Agent-Based Model

Michael Laver
Ernest Sergenti
Copyright Date: 2012
Pages: 292
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  • Book Info
    Party Competition: An Agent-Based Model
    Book Description:

    Party competition for votes in free and fair elections involves complex interactions by multiple actors in political landscapes that are continuously evolving, yet classical theoretical approaches to the subject leave many important questions unanswered. Here Michael Laver and Ernest Sergenti offer the first comprehensive treatment of party competition using the computational techniques of agent-based modeling. This exciting new technology enables researchers to model competition between several different political parties for the support of voters with widely varying preferences on many different issues. Laver and Sergenti model party competition as a true dynamic process in which political parties rise and fall, a process where different politicians attack the same political problem in very different ways, and where today's political actors, lacking perfect information about the potential consequences of their choices, must constantly adapt their behavior to yesterday's political outcomes.

    Party Competitionshows how agent-based modeling can be used to accurately reflect how political systems really work. It demonstrates that politicians who are satisfied with relatively modest vote shares often do better at winning votes than rivals who search ceaselessly for higher shares of the vote. It reveals that politicians who pay close attention to their personal preferences when setting party policy often have more success than opponents who focus solely on the preferences of voters, that some politicians have idiosyncratic "valence" advantages that enhance their electability--and much more.

    eISBN: 978-1-4008-4032-8
    Subjects: Political Science

Table of Contents

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  1. Front Matter
    (pp. i-iv)
  2. Table of Contents
    (pp. v-vi)
  3. Preface
    (pp. vii-xii)
  4. Acknowledgments
    (pp. xiii-xiv)
  5. Part One: Preliminaries

    • CHAPTER ONE Modeling Multiparty Competition
      (pp. 3-14)

      We hold these truths to be self-evident:

      Politics is dynamic. It evolves. It never stops; It is never at, norenrouteto, some static equilibrium. Politics evolves.

      Politics is complex. Political outputs today feed back as input to the political process tomorrow.

      Politicians are diverse. In particular, different politicians attack the same problem in different ways.

      Politics is not random. Systematic patterns in political outcomes invite systemic predictions, making a political “science” possible.

      Politics in modern democracies is largely the politics of representation. It concerns how the needs and desires, the hopes and fears of ordinary citizens affect national decision...

    • CHAPTER TWO Spatial Dynamics of Political Competition
      (pp. 15-27)

      Politicians compete with each other in many different ways. They trade on personal popularity; they attack the integrity and character of their opponents. They exploit, or are victims of, biased coverage in the news media. They hire advertising agencies to manipulate these same media. They practice dark arts and dirty tricks. Political competition in any given setting has many idiosyncratic features that are not at all amenable to general explanations. If we want to understand the close-in detail of any particular political system, we do best to ask people who have particular local knowledge and/or insight-“gurus” who specialize in the...

    • CHAPTER THREE A Baseline ABM of Party Competition
      (pp. 28-55)

      We just saw that party leaders involved in the complex dynamics of multiparty competition face analytically intractable decision problems. This implies that real party leaders use informal rules of thumb rather than formally provable best response strategies. Thisbehavioralassumption about party leaders motivates using agent-based models (ABMs) of decision making in complex dynamic settings. In the rest of this book, we develop and analyze an ABM of multiparty competition in multidimensional policy spaces.

      Recent examples of such models include widely cited and seminal work by Kollman, Miller, and Page (1992, 1998, 2003). Building on this, Laver developed an ABM...

    • CHAPTER FOUR Systematically Interrogating Agent-Based Models
      (pp. 56-82)

      We have shown that dynamic multiparty competition is analytically intractable, both for third party analysts and for the real politicians involved. This led us to specify a computational agent-based model of multiparty competition, and we start computational investigations of this model in chapter 5. Before we can do this, however, we must settle several important matters of experimental design and methodology.Experimental designissues concern the particular simulations we specify, and why.Methodologicalissues concern how we estimate quantities of interest from the output of the simulations we specify. We want to be clear before we start any computation that...

  6. Part Two: The Basic Model

    • CHAPTER FIVE Benchmarking the Baseline Model
      (pp. 85-105)

      Having set out our methods in chapter 4, we are now at last in a position to start investigating multiparty competition using the baseline model we specified in chapter 3. As we said when setting out our plan of campaign, we start simple in this chapter and build up to a more complex and realistic model of party competition in subsequent chapters. We need to understand the basic processes of dynamic multiparty competition in a simple setting before we move on to study complications such as endogenous political parties, diverse sets of decision rules, voters who care about more than...

    • CHAPTER SIX Endogenous Parties, Interaction of Different Decision Rules
      (pp. 106-131)

      We have so far made the preposterous assumption that political parties come to us as gifts from God or Nature. We did this to get started in our investigations of party competition, but we all know this is not true. We know that political parties are endogenousoutputsof the process of party competition, not exogenous inputs to it. Any halfway realistic model of multiparty competition must treat the set of competing political parties as endogenous. This has of course not escaped the attention of scholars modeling party competition in the classical analytical tradition, but it has proved a hard...

    • CHAPTER SEVEN New Decision Rules, New Rule Features
      (pp. 132-156)

      We went far beyond our baseline model of party multiparty competition in the previous chapter, and also beyond much of the existing work in this subject. We did this by modeling the set of competing parties as an endogenous output of, not an exogenous input to, the dynamic process of multiparty competition, and by modeling competition between party leaders using different decision rules in this complex environment. Those decision rules for setting party policy, however, were limited to the set of three baseline rules we specified in chapter 3: Sticker, Aggregator, and Hunter. We now go well beyond this to...

  7. Part Three: Extensions and Empirics

    • CHAPTER EIGHT The Evolutionary Dynamics of Decision Rule Selection
      (pp. 159-182)

      Our model of endogenous party birth and death in a dynamic party system uses updated vote share as a measure of party fitness. As we have seen, this creates a “survival-of-the-fittest” evolutionary environment in which fitter parties tend to survive and less fit parties tend to die. As a result, parties using more effective decision rules tend systematically to live longer. In this chapter, we develop our evolutionary model of dynamic party competition by moving beyond the substantively unrealistic assumption that leaders of new political parties pick their decision rules at random. We now assume theyare more likely to...

    • CHAPTER NINE Nonpolicy Factors in Party Competition
      (pp. 183-205)

      Spatial models of party competition, of their essence, deal with how politicians compete with each other by setting rival policy positions. They are, as we have seen, models of competitive spatial location, where the spaces under consideration arepolicyspaces that describe how voters feel about different potential outcomes of the policy process. Clearly,nonpolicy factorsmay also have an impact on political competition. Indeed local commentators often stress nonpolicy factors when interpreting the current state of politics in any given setting. These include, but are by no means confined to, the intangible but nonetheless potent charisma of certain candidates;...

    • CHAPTER TEN Party Leaders with Policy Preferences
      (pp. 206-227)

      Up until now we have been modeling a political world wherevoterscare about policy butparty leaderscompletely ignore their own personal policy preferences when they adapt party policy to evolving patterns of voter support. This is also the world described by classical Downsian spatial models of party competition. In this chapter, we adapt our dynamic model of multiparty competition to take into account the possibility thatparty leaders take their own preferences into account when they set party policy. If they do this, they must make trade-offs between satisfying their private policy preferences and some other objective, whether...

    • CHAPTER ELEVEN Using Theoretical Models to Analyze Real Party Systems
      (pp. 228-257)

      We build theoretical models to help us understand the world. We call our own model a model of “party competition,” our agents “party leaders” and “voters,” because we believe these artificial constructs do in some meaningful way resemble party competition, party leaders, and voters in real political settings. The real political settings that interest us involve party competition in modern democracies, more precisely, in a list of specific postwar democracies about which we have some systematic knowledge.¹ In this chapter, we use our model to analyze recent party competition in these postwar democracies in order to satisfy ourselves that empirical...

    • CHAPTER TWELVE In Conclusion
      (pp. 258-266)

      We have come a long way together since the beginning of this book. We started with the twin premises that understanding multiparty competition is a core concern for everyone interested in representative democracy and that we must understand multiparty competition as an evolving dynamic system, not a stationary state. Given these premises, we investigated the dynamics of multiparty competition using computational agent-based modeling, a new technology that, rigorously deployed, is ideally suited to providing systematic answers to the types of question we want to ask. This allows us to model decision making by party leaders, in what is clearly an...

  8. References
    (pp. 267-274)
  9. Index
    (pp. 275-278)