Identification: Why do we need it, how to use it?

The need for identification methods in measurement problems is considered. The basic concepts of the identification terminology are defined. The identification of linear dynamic systems is studied. A guideline is given to help the less experienced user to make a consistent selection in the large variety of available methods to solve an identification problem. A questionnaire is proposed to guide the user of identification techniques toward a suitable approach to model linear dynamic systems. The consequences of misuse of identification methods are also illustrated