Nov 25, 2025 · What is lavaan? The lavaan package is developed to provide useRs, researchers and teachers a free open-source, but commercial-quality package for latent variable modeling.

If you are new to lavaan, this is the place to start. In this tutorial, we introduce the basic components of lavaan: the model syntax, the fitting functions (cfa, sem and growth), and the …

The lavaan package automatically makes the distinction between variances and residual variances. In our example, the expression y1 ~~ y5 allows the residual variances of the two …

In lavaan, a typical model is simply a set (or system) of regression formulas, where some variables (starting with an ‘ f ’ below) may be latent. For example:

If you wish to fit non-standard models or if you don’t like the idea that things are done for you automatically, you can use the lower-level function lavaan() instead, where you have full control.

If the missing mechanism is MCAR (missing completely at random) or MAR (missing at random), the lavaan package provides case-wise (or ‘full information’) maximum likelihood estimation. …

This means that before installing lavaan, you should have installed a recent version (>= 4.0.0) of R. You can download the latest version of R from the R-project website.

The example illustrates the use of the ":=" operator in the lavaan model syntax. This operator ‘defines’ new parameters which take on values that are an arbitrary function of the original …

In general, to fix a parameter in a lavaan formula, you need to pre-multiply the corresponding variable in the formula by a numerical value. This is called the pre-multiplication mechanism …

lavaan outputs all the information you need: a large number of fit measures, modification indices, standardized solutions, and technical information that is stored in a fitted lavaan object