NetLogo Models Library:
IABM Textbook/chapter 7

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Voting Sensitivity Analysis

If you download the NetLogo application, this model is included. You can also Try running it in NetLogo Web

ACKNOWLEDGMENT

This model is from Chapter Seven of the book "Introduction to Agent-Based Modeling: Modeling Natural, Social and Engineered Complex Systems with NetLogo", by Uri Wilensky & William Rand.

• Wilensky, U. & Rand, W. (2015). Introduction to Agent-Based Modeling: Modeling Natural, Social and Engineered Complex Systems with NetLogo. Cambridge, MA. MIT Press.

This model is in the IABM Textbook folder of the NetLogo Models Library. The model, as well as any updates to the model, can also be found on the textbook website: http://www.intro-to-abm.com/.

WHAT IS IT?

This model is a simple cellular automaton that simulates voting distribution by having each patch take a "vote" of its eight surrounding neighbors, then perhaps change its own vote according to the outcome. The sensitivity version of this model alters the original model by allowing the user to specify the initial percentage of the green patches in the model and to test whether the model's behavior is sensitive to the initial percentages of the colors.

HOW TO USE IT

Click the SETUP button to create an approximately equal but random distribution of blue and green patches. Click GO to run the simulation.

When both switches are off, the central patch changes its color to match the majority vote, but if there is a 4-4 tie, then it does not change.

If the CHANGE-VOTE-IF-TIED? switch is on, then in the case of a tie, the central patch will always change its vote.

If the AWARD-CLOSE-CALLS-TO-LOSER? switch is on, then if the result is 5-3, the central patch votes with the losing side instead of the winning side.

The INITIAL-GREEN-PCT slider controls the percentage of initial green patches.

THINGS TO NOTICE

How does the INITIAL-GREEN-PCT affect the results of the model?

THINGS TO TRY

Run the sensitivity-experiment in BehaviorSpace and graph the results using your favorite statistical analysis package.

EXTENDING THE MODEL

The model currently has two monitors that show the number of green and blue patches. It would be nice to add a plot that shows the relationship between these two numbers. It could be a line plot showing the percentage of green patches, or it could be a histogram showing the count for each color. Why don't you try both and see which one you like best?

RELATED MODELS

This is a slight variant of the Voting model in the Social Sciences section of the NetLogo models library.

It is a companion model to another model from Chapter seven of the Textbook, Voting Component Verification.

Another related model is Ising in the Chemistry and Physics section of the NetLogo models library. Although it's a physics model, the rules are very similar.

CREDITS AND REFERENCES

This model is described in Rudy Rucker's "Artificial Life Lab", published in 1993 by Waite Group Press.

HOW TO CITE

This model is part of the textbook, “Introduction to Agent-Based Modeling: Modeling Natural, Social and Engineered Complex Systems with NetLogo.”

If you mention this model or the NetLogo software in a publication, we ask that you include the citations below.

For the model itself:

• Rand, W., Wilensky, U. (2008). NetLogo Voting Sensitivity Analysis model. http://ccl.northwestern.edu/netlogo/models/VotingSensitivityAnalysis. Center for Connected Learning and Computer-Based Modeling, Northwestern Institute on Complex Systems, Northwestern University, Evanston, IL.

Please cite the NetLogo software as:

• Wilensky, U. (1999). NetLogo. http://ccl.northwestern.edu/netlogo/. Center for Connected Learning and Computer-Based Modeling, Northwestern University, Evanston, IL.

Please cite the textbook as:

• Wilensky, U. & Rand, W. (2015). Introduction to Agent-Based Modeling: Modeling Natural, Social and Engineered Complex Systems with NetLogo. Cambridge, MA. MIT Press.

COPYRIGHT AND LICENSE

Copyright 2008 Uri Wilensky.

This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License. To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-sa/3.0/ or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.

Commercial licenses are also available. To inquire about commercial licenses, please contact Uri Wilensky at uri@northwestern.edu.

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