{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

VensimUsersGuide chaps 4 5 6

# VensimUsersGuide chaps 4 5 6 - 4 Causal Loop Diagramming...

This preview shows pages 1–3. Sign up to view the full content.

41 4 Causal Loop Diagramming Vensim Models This chapter describes causal loop. Causal loop diagrams are called that because each link has a causal interpretation. An arrow going from A to B indicates that A causes B. Causal loop diagrams can be very helpful in conceptualizing and communicating structures. Many people find causal loop diagramming to be very helpful even when no simulation model is created, while others feel they can be harmful if done in isolation. This chapter is primarily about technique, and is useful to work through even if you choose not to build any additional causal loop diagrams. Causal loop diagrams are also often called influence diagrams. Causal loop diagrams do not show accumulations (levels or stocks) in a system. Construction of stock and flow diagrams is covered in Chapter 5. However, even if you intend to build only stock and flow diagrams, we recommend that you start with this chapter as many of the basic drawing mechanics are the same and they are covered in more detail here. It is important to note that causal loop diagrams and stock and flow diagrams are not simulation models. Simulation models, like the one used in Chapter 3, attach algebraic relationships to all the variables appearing in a diagram. In Chapter 6, "Building a Simulation Model" we describe how to create a simulation model. If you are using Vensim Professional or DSS you can skip building model diagrams altogether enter equations directly. Almost all people, however, find it easier to build up models diagrammatically. Drawing Sketches When a Sketch Tool is selected, that tool remains active until you select another tool. A single click (press and release) with the mouse button applies the tool to the sketch. The Lock tool provides the standard mouse cursor. The Lock tool can be used for selecting sketch objects (they highlight black) and for changing options. Sketch objects cannot be moved with the Lock tool. Tip — you can select the Lock tool by pressing the Esc key, or the keyboard number 1. The Move/Size tool is used for moving sketch objects around, including resizing variables and boxes, and reshaping arrows. The other sketch tools also allow you to move objects. Variable sketch tools ( Variable Box Variable and other variable tools you may configure) and the default setting for the Rates tool bring up editing boxes (for naming the Variable or Rate) when applied to the sketch. The Sketch Comment tool brings up a dialog box.

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
4: Vensim User’s Guide 42 The Arrow tool starts an arrow. To do this make a single click (press and release) of the mouse button on the middle of the starting word, then finish with another single click on the middle of the ending word. Arrows (curved) can take one intermediate point on a sketch with an extra mouse click.
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

### What students are saying

• As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

Kiran Temple University Fox School of Business ‘17, Course Hero Intern

• I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

Dana University of Pennsylvania ‘17, Course Hero Intern

• The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

Jill Tulane University ‘16, Course Hero Intern