1. A tangible computer-readable storage medium storing computer-executable instructions for execution by a processor, the medium storing one or more instructions for: registering, with a modeling application, one or more rules related to an entity associated with a model; receiving input specifying a value of a first attribute associated with the entity; and applying the one or more registered rules to the value of the first attribute to: infer a value of a second attribute associated with the entity or another entity associated with the model, or validate the value of the first attribute or the value of the second attribute.