15.5 The ldentification Problem Identification problem: whether we can estimate the parameters of the particular equation. (1) The particular equation is exactly identified: we can estimate the parameters of the particular equation (2) The equation is unidentified or under identified: we cannot estimate the parameters (3) The equation is over identified: there is more than one numerical value for one or more parameters of that equation15.5 The Identification Problem Identification problem: whether we can estimate the parameters of the particular equation. • （ 1 ） The particular equation is exactly identified: we can estimate the parameters of the particular equation. • （2）The equation is unidentified or under identified: we cannot estimate the parameters. • （3）The equation is over identified : there is more than one numerical value for one or more parameters of that equation