The `summary()` function gives a nice overview of a fitted model, but is for display only. If you need the actual numbers for further processing, you may prefer to use one of several 'extractor' functions. We have already seen the `coef()` function which extracts the estimated parameters of a fitted model. Other extractor functions are discussed below.

#### parameterEstimates

The `parameterEstimates` function extracts not only the values of the estimated parameters, but also the standard errors, the z-values, the standardized parameter values, and returns everything conveniently as a data frame. For example:

#### standardizedSolution

The `standardizedSolution()` function is similar to the `parameterEstimates()` function, but only shows the unstandardized and standardized parameter estimates.

#### fitted.values

The `fitted()` and `fitted.values()` functions return the model-implied (fitted) covariance matrix (and mean vector) of a fitted model:

#### residuals

The `resid()` or `residuals()` functions return (unstandardized) residuals of a fitted model. This is simply the difference between the observed and implied covariance matrix and mean vector. If the estimator is maximum likelihood, it is also possible to obtain the normalized and the standardized residuals (note: you may observe several `NA` values, but they can be safely ignored)

#### vcov

The function `vcov()` returns the estimated covariance matrix of the parameter estimates.

#### AIC and BIC

The `AIC()` and `BIC()` functions return the AIC and BIC values of a fitted model.

#### fitMeasures

The `fitMeasures()` function returns all the fit measures computed by lavaan as a named numeric vector.

If you only want the value of a single fit measure, say, the CFI, you give the name (in lower case) as the second argument:

Or you can provide a vector of fit measures, as in

#### inspect

If you want to peek inside a fitted lavaan object (the object that is returned by a call to `cfa()`, `sem()`or `growth()`), you can use the `inspect()` function, with a variety of options. By default, calling `inspect()` on a fitted lavaan object returns a list of the model matrices that are used internally to represent the model. The free parameters are nonzero integers.

To see the starting values of parameters in each model matrix, type

To see how lavaan internally represents a model, you can type

This is equivalent to the `parTable(fit)` function. The table that is returned here is called the 'parameter table'.

For more inspect options, see the help page for the lavaan class which you can find by typing the following: