Modelling is the attempt to reproduce real-world relationships within a mathematical or computer model.
It involves defining and quantifying relationships and building these into an internally self-consistent model that can then be subject to various forms of manipulation. The model may be relatively simple, e.g. involving forecasts of local traffic flows; or it may be complex, e.g. attempting to represent economic or environmental systems.
Modelling is mostly a forecasting method.
See also :