Purpose

What is the purpose of the model?
This is too often not clearly stated early on in the modelling process and should not only be the first question asked but the main guideline during the process as well.

Entities, state variables, and scales

What kinds of entities are in the model?
Agents, collectives, spatial units, global environment

By what state variables, or attributes, are these entities characterized?
E.g. age, sex, wealth, opinion, strategy; soil type, land costs; rainfall, price

What are the temporal and spatial resolutions and extents of the model?
E.g. one tick refers to one year, simulation runs from x to z, one patch refers to xy, and the “world” stretches over z.