ABSTRACT
Beck et al. (1993) argue that a model is a complex assemblage of constituent hypotheses. A model is based on a set of hypotheses that operate together to produce a set of outcomes that can then be compared with reality. They also suggest that there are three objectives to modelling: to predict the future, to identify the mechanisms crucial to the generation of patterns observed in reality, and to reconcile observed patterns with concepts via the model. They view the model as an essential tool in simulating reality. The simulation becomes the focus of study and, in particular, its relationship to observed patterns of phenomena. Beck (1991) outlines a threefold typology of models: metric, conceptual and physics-based. Metric models are based upon observations and try to characterize system response from these observed data. Observations are the driving force in developing these models, with empirical data providing the raw input into the model. Conceptual models identify the model structure before any data are collected. These models already have the important processes identified and use environmental data to calibrate these processes. Physics-based models work from first principles and build a physically coherent model of reality from these building blocks.
