When the Fit option is selected, values of the endogenous variables for the current period are used when the model is solved. All endogenous variables except the one variable for the equation being evaluated are replaced by their actual values. The fit option can be used to examine the fit of each of the equations in the model when considered separately, ignoring their interdependence in the model. The fit option can only be used for periods when historical values are available for all the endogenous variables.