Model validation is used to verify the
correctness of the system. Conceptual models can
be formally or informally validated, either by
statically analyzing the model or in the case of
formal specifications by applying formal
reasoning to prove the properties of the system. In
critical systems, it has been found that the activity
of formally modeling the system can in itself serve
to identify errors such as ambiguities and
conflicts, however the cost of creating formal
models can normally only be justified for high
assurance systems. .