Modeling May Be the Answer

by Ralph Brauer
The best way to incorporate system dynamics modeling into your decision-making process is to work with a trained modeler. Understand that modeling does not provide answers but rather frames options, and the collaboration of individuals who are familiar with system dynamics and who can probe your mental models is valuable. Models almost always address specific questions, so the better you can articulate the issue, the better the model.

If you already think you know the answer, you don’t need modeling.

You can put together your own version of the basic supply-demand idea we found so valuable by following these suggestions.

Use time as your unit of currency. Decide how you will define student demand in that currency. Our model uses the time required to support student learning and to channel student behavior. Many variations on that theme are possible, however.

Assign your students to three or four levels based on these demand criteria. Each level then is assigned a multiplier based on the time demands of the students in that level. The sum of total students in each level times the multiplier for that level equals total demand. Remember as you discuss this, you must have good, verifiable data for your calculations.

The supply side, or resource, calculation can be a little more complicated, but the internal discussion is worth the effort. The question you want to answer is: What does each component of the system contribute to satisfying the total time demand of the students? Again, our model uses numbers and qualifications of teachers as primary measures plus a variety of administrative and other factors that affect system functioning. As with demand, the data you use must be measurable.

With the basic supply-and-demand numbers worked out, you now have a snapshot of your system. To move to systemic analysis you need to explore what happens to this supply-and-demand relationship over time. What were the numbers last year and the year before? Where do you expect them to be next year? In two years? Now you are creating a dynamic mental model of your system.

Having outlined those changes you can move to explore the systemic “whys” that allow you to address policy questions. What has changed in your system over time that might have affected those variables? What seem to be the consequences of those changes? Are there secondary, delayed or otherwise easily overlooked consequences to those changes? Do those variables coincide with your mental model of where you thought the leverage points lay?

While this is cruder than a computer simulation, it has the value of reframing your resource-and-demand discussions and getting you to ask better questions of your system.