Building the Model

Step 4 Adding Connectors

Finally, Vensim PLE needs instructions about which elements depend on each other. In this case, the rate Get Sick depends on the number of susceptible people, the number of infected people and the infection fraction. Therefore we need to add connectors from each of these variables to the rate Get Sick.

Procedure:

• Click on the Connector button on the toolbar.
• Click and release on a variable then click and release on the object you want to connect to.
• Repeat this process to connect each of Susceptible People, Infected People, and Infection Fraction to Get Sick.

Adding Connectors

NOTICE: At first, the arrows may cut through other objects or object names. You can reposition connecting arrows to make your graph more organized. To do so, click on either the Selection button or the Connector button then click on the small empty circle near the middle of the arrow and drag it. As you drag, the arrow will change its length and arc. Try to keep your arrows simple and direct without obscuring other objects or names.