Editing Discrepancy function (section)

==Examples==
There are several basic types of discrepancy functions, including [[maximum likelihood]] (ML), [[generalized least squares]] (GLS), and [[ordinary least squares]] (OLS), which are considered the "classical" discrepancy functions.<ref>{{cite web | title = Discrepancy Functions Used in SEM | url = http://www2.gsu.edu/~mkteer/discrep.html | accessdate = 2008-08-18 | archive-date = 2008-08-21 | archive-url = https://web.archive.org/web/20080821171312/http://www.gsu.edu/~mkteer/discrep.html | url-status = dead }}</ref>  Discrepancy functions all meet the following basic criteria:

*They are non-negative, i.e., always greater than or equal to zero. 
*They are zero only if the fit is perfect, i.e., if the model and parameter estimates perfectly reproduce the observed data. 
*The discrepancy function is a continuous function of the elements of '''S''', the sample covariance matrix, and '''Σ(θ)''', the "reproduced" estimate of '''S''' obtained by using the parameter estimates and the structural model.

In order for "maximum likelihood" to meet the first criterion, it is used in a revised form as the [[Deviance (statistics)|deviance]].