What is behavior-over-time graph (BOT)?

A behavior-over-time graph, or BOT, plots one or more variables on the vertical axis against time on the horizontal axis. The shape of the line, such as rising, leveling off, or cycling, is the focus. It matters because it forces a team to state what pattern they are trying to explain before they build any model.

How it works

BOTs are used at two moments. Early on, a sketch drawn by hand shows how people think a variable has behaved and might behave, which becomes the reference mode. Later, the simulation draws its own BOT, and the team compares the two. A match in shape, timing, and size is evidence that the model's structure may be right, which is part of validation.

A good BOT has labeled axes with units, a clear time span, and few lines. Putting related variables on one graph, such as a stock and its main inflow, reveals delays and feedback, because the peak of one line lags the other. The common patterns are exponential growth, S-shaped growth, goal-seeking, and oscillation. Naming the pattern narrows down which feedback loops to look for.

Example

Say a team sketches monthly active users for the last 24 months: about 1,000 at the start, rising to 20,000 at month 12, then flattening near 25,000. The line curves upward and then bends to flat. That shape is S-shaped growth, which suggests a reinforcing loop early and a limit later, such as market size. A line drawn only as a table of numbers would hide this. This is an illustration with round numbers.

How to model it in Machinations

Add a chart to the Pool or Register you care about and Play the diagram. The chart is your BOT: read its shape, timing, and size. Then set it beside the real series you recorded, for example in a spreadsheet, and compare the two shapes. Use a Lever to change a parameter and see how the shape changes.