Agent-Based Modelling in Economics E-Book

Lynne Hamill

• Herausgeber: John Wiley & Sons
• Kategorie: Wissenschaft und neue Technologien
• Sprache: Englisch

Seitenzahl: 441

Veröffentlichungsjahr: 2015

Beschreibung

Agent-based modelling in economics

Lynne Hamill and Nigel Gilbert, Centre for Research in Social Simulation (CRESS), University of Surrey, UK

New methods of economic modelling have been sought as a result of the global economic downturn in 2008.This unique book highlights the benefits of an agent-based modelling (ABM) approach. It demonstrates how ABM can easily handle complexity: heterogeneous people, households and firms interacting dynamically. Unlike traditional methods, ABM does not require people or firms to optimise or economic systems to reach equilibrium. ABM offers a way to link micro foundations directly to the macro situation. 

Key features:

• Introduces the concept of agent-based modelling and shows how it differs from existing approaches.
• Provides a theoretical and methodological rationale for using ABM in economics, along with practical advice on how to design and create the models.
• Each chapter starts with a short summary of the relevant economic theory and then shows how to apply ABM.
• Explores both topics covered in basic economics textbooks and current important policy themes; unemployment, exchange rates, banking and environmental issues.
• Describes the models in pseudocode, enabling the reader to develop programs in their chosen language.
• Supported by a website featuring the NetLogo models described in the book.

Agent-based Modelling in Economics provides students and researchers with the skills to design, implement, and analyze agent-based models. Third year undergraduate, master and doctoral students, faculty and professional economists will find this book an invaluable resource.

Leseprobe

Table of Contents

Cover

Title Page

Preface

Copyright notices

1 Why agent-based modelling is useful for economists

1.1 Introduction

1.2 A very brief history of economic modelling

1.3 What is ABM?

1.4 The three themes of this book

1.5 Details of chapters

References

2 Starting agent-based modelling

2.1 Introduction

2.2 A simple market: the basic model

2.3 The basic framework

2.4 Enhancing the basic model: adding prices

2.5 Enhancing the model: selecting traders

2.6 Final enhancement: more economically rational agents

2.7 Running experiments

2.8 Discussion

Appendix 2.A The example model: full version

References

3 Heterogeneous demand

3.1 Introduction

3.2 Modelling basic consumer demand theory

3.3 Practical demand modelling

3.4 Discussion

Appendix 3.A How to do it

References

4 Social demand

4.1 Introduction

4.2 Social networks

4.3 Threshold models

4.4 Adoption of innovative products

4.5 Case study: household adoption of fixed-line phones in Britain

4.6 Discussion

Appendix 4.A How to do it

References

5 Benefits of barter

5.1 Introduction

5.2 One-to-one barter

5.3 Red Cross parcels

5.4 Discussion

Appendix 5.A How to do it

References

6 The market

6.1 Introduction

6.2 Cournot–Nash model

6.3 Market model

6.4 Digital world model

6.5 Discussion

Appendix 6.A How to do it

References

7 Labour market

7.1 Introduction

7.2 A simple labour market model

7.3 Discussion

Appendix 7.A How to do it

References

8 International trade

8.1 Introduction

8.2 Models

8.3 Discussion

Appendix 8.A How to do it

References

9 Banking

9.1 Introduction

9.2 The banking model

9.3 Discussion

Appendix 9.A How to do it

References

10 Tragedy of the commons

10.1 Introduction

10.2 Model

10.3 Discussion

Appendix 10.A How to do it

References

11 Summary and conclusions

11.1 Introduction

11.2 The models

11.3 What makes a good model?

11.4 Pros and cons of ABM

References

Further reading and resources

Index

End User License Agreement

List of Tables

Chapter 03

Table 3.1 Results: estimated effect of the imposition of a 10% ad valorem tax on food.

Chapter 04

Table 4.1 Summary of results for threshold models: adoption rates after 10 and 25 periods.

Chapter 05

Table 5.1 Examples of random trading.

Table 5.2 Initial prices under the three pricing regimes with rations of 50 cigarettes and 50 chocolates.

Chapter 06

Table 6.1 Results: variation in total output.

Chapter 07

Table 7.1 Unemployment rate and duration of unemployment by age: April to June 2013, United Kingdom, seasonally adjusted.

Table 7.2 Results from the simple labour market model.

Chapter 08

Table 8.1 International imports and exports in goods and services as per cent of GDP (2012).

Table 8.2 Model assumptions and initial values.

Table 8.3 Results: Inflation scenario – a 10% increase in prices.

Table 8.4 Results: Effect of exogenous 10% drop in demand.

Table 8.5 Results: Fiscal policy scenario – 10

%

cut in government expenditure.

Chapter 09

Table 9.1 Example of the cumulative power of repayments: £1000 deposit lent out over 3 years.

Table 9.2 Results from a very simple model after 10 years.

Chapter 10

Table 10.1 Example of cooperation generating benefits.

Table 10.2 Effect of imposing limits on the number of cows each commoner can graze on the meadow.

Chapter 11

Table 11.1 Summary of models.

List of Illustrations

Chapter 02

Figure 2.1

NetLogo interface window showing the market model after two ticks.

Figure 2.2

The NetLogo code window showing the top portion of the market model code.

Figure 2.3

The interface of the model enhanced with a plot of the average amount spent.

Figure 2.4

A NetLogo runtime error

.

Figure 2.A.1

Screenshot of the interface of the final version of the model.

Chapter 03

Figure 3.1

Budget shares by household income: United Kingdom, 2010.

Figure 3.2

Effect of a change in price on demand.

Figure 3.3

The budget distribution model (based on 30 runs, each with 1000 agents).

Figure 3.4

Assumed budget shares (alphas) for food.

Figure 3.5

Results: distribution of budget shares generated by model (based on a single run using 1000 agents). (A single run is used as this model serves only to illustrate the methodology and has no practical value.)

Figure 3.6

Results: demand for food based on a Cobb–Douglas utility function (based on a single run of 1000 agents).

Figure 3.7

Results: change in utility by budget following a 10% increase in the price of food (based on a single run with 1000 agents).

Figure 3.8

Results: how total expenditure on food is distributed across the budget quintiles compared to the actual distribution (based on 30 runs with 1000 agents).

Figure 3.A.1

Screenshot of inputs for the practical demand model: food.

Figure 3.A.2

Screenshot of outputs of practical demand program: food.

Chapter 04

Figure 4.1

Effect of 5% of agents ‘social shifting’: per cent of agents for whom social circles changed over time (in composition or size). 1000 agents, 30 runs (1).

Figure 4.2

The classic S-curve of adoption.

Figure 4.3

Infection model results: innovators 2.5% (1000 agents, 30 runs).

Figure 4.4

Influence model results: innovators 2.5% and social circles average 28 (social reach = 30) with social shifting: thresholds distributed uniformly or normally (1) (1000 agents, 30 runs).

Figure 4.5

Adoption of domestic appliances in the United Kingdom (1).

Figure 4.6

Adoption of communication devices by households in the United Kingdom.

Figure 4.7

Adoption of phones by households’ income, Great Britain: 1964*–2001.

Figure 4.8

Results of the model using an income threshold only and no network effect (1000 agents, 30 runs).

Figure 4.9

Model results compared to actual: phone adoption (1000 agents, 30 runs). Standard deviations not shown to simplify diagrams.

Figure 4.A.1

Screenshot for the social circles model.

Figure 4.A.2

Screenshot of the threshold model.

Figure 4.A.3

Screenshot of the phone adoption model.

Chapter 05

Figure 5.1

Traditional Edgeworth Box example

.

Figure 5.2

Trading with an auctioneer

.

Figure 5.3

Trading with an auctioneer when there is a shortage

.

Figure 5.4

Trading in the Edgeworth Box without an auctioneer

.

Figure 5.5

Increases in utility as a result of trade under random pricing

.

Figure 5.6

Trading under different price-setting regimes

.

Figure 5.7

Examples of shifts in demand and supply curves

.

Figure 5.8

Prices and quantities traded under different price-setting regimes

.

Figure 5.9

Examples of trading patterns with a chocolate shortage

.

Figure 5.10

Prices and quantities traded under different price-setting regimes with a chocolate shortage

.

Figure 5.A.1

Screenshot of the Edgeworth Box game

.

Figure 5.A.2

Screenshot of the Edgeworth Box random model

.

Figure 5.A.3

Screenshot of the Red Cross parcels model

.

Chapter 06

Figure 6.1

Shops: example of aggregate demand.

Figure 6.2

Shops model results: quantities sold and number of shops surviving, by time: industry size 10 (30 runs).

Figure 6.3

Shops model results: varying the industry size.

Figure 6.4

Digital world results: example of supply and demand curves.

Figure 6.5

Digital world model results: life span of sellers (100 runs).

Figure 6.A.1

Screenshot for the Cournot–Nash model.

Figure 6.A.2

Screenshot of the shops model.

Figure 6.A.3

Screenshot of the digital world model.

Chapter 07

Figure 7.1

Unemployment level and the unemployment flows in the United Kingdom: 2001–2013.

Figure 7.2

Labour market flows in the United Kingdom: comparing Q1 to Q2, 2013 (see Box 7.1 for definitions).

Figure 7.3

Hazard rates, United Kingdom: 2001–2013.

Figure 7.4

Results of model: an example of the distribution of wages generated by the model.

Figure 7.5

Results from the job search model.

Figure 7.6

Simple labour market model.

Figure 7.7

Unemployment rate in south-east England: 1992–2013.

Figure 7.8

Results: examples of the unemployment rate (%) based on maximum wage increase of 5% (as illustrated in Box 7.11)

.

Figure 7.A.1

Screenshot of wage distribution model.

Figure 7.A.2

Screenshot of job search model.

Figure 7.A.3

Screenshot of Guildford labour market model.

Chapter 08

Figure 8.1

The Trilemma.

Figure 8.2

Fluctuations in the exchange rates of UK pounds.

Figure 8.3

Effective exchange rates: the United Kingdom, the United States and Eurozone, 2000–2013.

Figure 8.4

Results: dynamics of the effect of a 10% increase in prices in the United Kingdom.

Figure 8.5

Results: dynamics of effect of exogenous 10% drop in demand in the United Kingdom.

Figure 8.6

Results: dynamics of the effect of a 10% cut in taxes in the United Kingdom.

Figure 8.A.1

Screenshot for the International Trade model.

Chapter 09

Figure 9.1

Example of the cumulative power of repayments: initial £1000 deposit.

Figure 9.2

Summary of the banking model.

Figure 9.3

Examples of the supply of new loans.

Figure 9.4

Results: mortgages compared to consumer loans: bank metrics and the economy (10 runs).

Figure 9.5

Results: household savings: mortgages and consumer loans compared (10 runs).

Figure 9.6

Results: a shock to mortgage lending: bank metrics (10 runs).

Figure 9.7

Results: a shock to lending, mortgages and consumer loans: bank metrics (10 runs).

Figure 9.A.1

Screenshot of banking model.

Chapter 10

Figure 10.1

Cows supported and grass available when the grass grows.

(The standard deviations are not shown to keep the diagrams clear).

Figure 10.2

Meadow management model results: limit of 1000 cows per commoner. 15 runs over 25 years.

Figure 10.3

The number of cows at the end of each year with a limit of 60 or 50 per commoner.

Figure 10.A.1

Screenshot of the carrying capacity model

.

Figure 10.A.2

Screenshot of the meadow management model

.

Guide

Cover

Table of Contents

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Agent-Based Modelling in Economics

Lynne Hamill and Nigel Gilbert

Centre for Research in Social Simulation (CRESS),University of Surrey, UK

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