Segregation Simulator Help

This segregation applet simulates the movement of people between houses within a "city."  The city is divided into 10 x 10 "tracts" which are in turn divided into a grid of smaller squares. Each small square in the city represents a house that can be vacant (white) or occupied by a red or blue or, in three-color mode, a green square. If a square has a yellow background it is restricted, in some way, to only certain colors.

Running Controls - Start, Stop, Reset, Shuffle, Counters

The Start and Stop buttons begin and pause the simulation while the drop-down menu next to the Stop button changes the speed of the simulation.  The Reset City button restores the arrangement of houses to the state at the start of the previous simulation.  The shuffle houses button distributes the colors randomly throughout the city. 

The Reset Counters button resets the Move/Attempts counters to 0. The Move/Attempt counters display the numbers of moves that have actually occurred in the simulation and the number of attempted moves. An attempted move will not result in an actual move if a house is selected to move into a new location forbidden by the current moving rules (see below). 

Indices of Segregation

The Indices of Segregation provide a numerical representation of how segregated the city is. 

For further discussion see the Racial Residential Segregation Measurement Project. The indices used for the simulator are based on Michael J. White, 1986, "Segregation and Diversity Measures in Population Distribution." Population Index, Vol. 52, 198-221. Click here for a more detailed description (pdf file).

Moving Rules

The 3x3 grids in the Moving Rules section visually depict the preferences that control moving to another square. The middle square in each grid indicates the color of the house to be moved, and the number of colored squares around the middle signifies the number of neighbors of a particular color preferred and tolerated (minimum of zero, maximum of 8. The location of these squares around the middle is irrelevant; only the total number is important.) You can change the squares from vacant to occupied (and vice versa) by clicking on the squares surrounding the center house in each grid.

City Settings

The size of the city grid can be selected with the City Grid Size control (10x10 to 120x120).

The city can be populated with two (red & blue) or three (red, blue, & green) different house colors.

Population Help

The percentages of house colors can be adjusted using the slider controls. Note that the sum of the percentage of each color and the vacancy rate always equals 100%. You may lock a percentage to stay fixed while adjusting other sliders by selecting the "Lock" box next to a slider. Once you have adjusted the sliders, you must press the "Apply and Shuffle" button to change the city population to the slider settings. This button will also randomize the location of the houses in the city.

Drawing Tools

The drawing tools allow you to change colors on the grid or to create vacancies. The "Pen" function changes one house at a time; the "Rectangle" function changes blocks of houses simultaneously.