- noun a small version of something larger
- noun a good example of something
- noun a particular type of product produced at a particular time
- noun a simplified description of a system, often in mathematical form, designed to make calculation simpler
- noun a person whose job is to wear new clothes to show them to possible buyers
- noun a description in the form of mathematical data
- noun a small copy of something made in order to show what it will look like when finished
- noun a style, type or version of a product
- verb to make a computerised model of a new product or of a system, e.g. the economic system
- A scale representation of an object, system, or building used for structural, mechanical, or aesthetic analysis.
- An object which is built to represent a component, circuit, device, piece of equipment, system, or another object. It can serve, for instance, for illustration, demonstration, or study.
- A mathematical, physical, or conceptual representation utilized to help understand a component, circuit, device, piece of equipment, system, mechanism, process, or phenomenon. Such a representation may, for example, help understand a complex circuit or device through one or more analogies.
- A specific style or design of a component, circuit, device, piece of equipment, system.
- (written as Model)
Models are simplified versions of a complex reality usually where there is considerable interdependence between the variables from which they are constructed. Their main use is to predict the effect of exogenous changes. Two broad kinds of modelling are done in health economics. One is the general kind employed throughout economics, which might be termed 'theoretical modelling', in which empirical characteristics are assumed (like transitivity of preferences) and general implications derived through an essentially analytical process of reasoning. The use of utility theory to model individual choices is a good example, from which is derived the implication that demand curves have a negative slope. The other is empirical modelling, where empirical relationships are postulated and interest focuses on simulating and quantifying the cause-and-effect relationships, elasticities and the like. Some modelling is relatively theory-free and is mainly concerned with forecasting by the extrapolation of past trends, with due allowance for interaction between determining variables but without necessarily any prior notion of the nature of such interactions.
In health economics, empirical modelling has assumed considerable importance in cost-effectiveness analysis and related techniques. It is often necessary to construct models that project costs and consequences beyond the endpoints of clinical trials in order to estimate both clinical effectiveness and cost-effectiveness. Such a model may be a theoretical decision analytic model using aggregated data or an empirical model using patient-level data. In epidemiology a distinction is made between cohort modelling (where all modelled individuals share similar characteristics at the outset) and micropopulation simulation modelling (which can represent the mixed nature of real populations or communities).
Critical issues in empirical economic modelling include relevance (e.g. the embodiment of appropriate comparator s), having an appropriate time horizon (e.g. consequences that are modelled over a realistic time horizon), taking a relevant perspective (e.g. one relevant for decision-makers), embodying relevant outcomes (e.g. final, intermediate or surrogate), making realistic assumptions (e.g. concerning adverse events) and having robust mathematical descriptions and appropriate modelling techniques (e.g. using sensitivity analysis, discounting).
Information & Library Science
- noun a theoretical statement of how a system will work which people can copy to achieve the same results
- noun a way of explaining how something works
- noun a representation (roughly to scale) of the ground over which an operation will take place, which is used as an aid to briefing the participants
Origin & History of “model”
Other English descendants of modus include modern, modicum (15th c.), modify (14th c.), and of course mode (16th c.) itself (of which mood ‘set of verb forms’ is an alteration).