Once you’ve decided the general boundary of your system—what you’ll focus on, and what you won’t—it is useful to draw simple graphs to describe the changing behaviors of the key variables in the system.
These graphs, called behavior-over-time graphs, encourage dynamic rather than static thinking, shifting focus from single events to changing patterns of behavior. This process encourages deeper thinking about what is changing and over what time frame. For students, graphs also act as another, visual way to communicate their thoughts and ideas.
When creating a behavior-over-time graph remember that the focus is on behavior changing over time, therefore, the x or horizontal axis must represent time. You can use any meaninful measurement: seconds, days, weeks, months, decades, and so on.
The behavior that is changing is shown on the y or vertical axis. You can plot any variable that increases or decreases. Often there's a standard measure you can use, although you may want to plot a variable that is not easily measured, such as a character's happiness or degree of team spirit. This will require use of a scale, such a 0-10, or you may label with y-axis with appropriate adjectives, such as "poor" at the bottom, "average" in the middle, and "superior" at the top.
As you look at behavior over time, you may find that the change is linear or exponential (upward or downward), or the pattern may oscillate. The question you would next consider is what set of interrelationships may be driving the behavior you've described in the graph.