Free Parameter

A free parameter is a number used to define a theory thoroughly enough so as to make useful predictions. This number should be determined by experiment but some theories include parameters that have not been verified by observation.
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A numerical value in a structural model (see Structural Equation Modeling ) that is part of the model, but is not fixed at any particular value by the model hypothesis. Free parameters are estimated by the program using iterative methods. Free parameters are indicated in the PATH1 language with integers placed between dashes on an arrow or a wire . For example, the following paths both have the free parameter 14.
(F1)-14->[X1]
(e1)-14-(e1)
If two different coefficients have the same free parameter number, as in the above example, then both will of necessity be assigned the same numerical value. Simple equality constraints on numerical coefficients are thus imposed by assigning them the same free parameter number.