Model development includes gathering data, defining variables, relationships between variables, finding equations, solving equations, and finally interpret model and revise model.Initially we can have...

Model development includes gathering data, defining variables, relationships between variables, finding equations, solving equations, and finally interpret model and revise model.Initially we can have very basic model with few assumptions. After we have initial model, we can always revise our model by add more variables or assumptions to make our model to be a better model.Keep in mind, there is no perfect model.But there is always a better model.The characteristics of modeling is developing simple model first and refine to better one and refine to acceptable one.