FitStack                Up-dates association parameters of the nominal
                        model
ItemData                Prepares data for up-dating scale value
                        parameters of nominal model
ItemGPCM.data           Creates data frame up-dating phi parameters of
                        the gpcm.
ItemLoop                loops through items and up-dates estimates of
                        scale values for each item in Nominal Model
Scale                   Imposes scaling constraint to identify
                        parameters of the LMA (nominal) model
ScaleGPCM               Imposes scaling constraint to identify
                        parameters of LMA (GPCM)
StackData               Prepares data for up-dating association
                        parameters of a multidimensional nominal LMA
StackDataGPCM           Prepares data for up-dating association
                        parameters of LMA (GPCM) model
convergence.stats       Computes statistics to assess convergence of
                        the nominal model
convergenceGPCM         Computes statistics to assess convergence for
                        generalized partial credit models
dass                    Dateframe of responses to items from
                        depression, anxiety, and stress scales
error.check             Checks for basic errors in input to the
                        'ple.lma' function
fit.gpcm                Fits LMA model where category scale values
                        equal a_im * x_j
fit.independence        Fits the log-linear model of independence
fit.nominal             Fits the nominal model
fit.rasch               Fits an LMA using fixed category scores
fitStackGPCM            Up-dates association parameters of the GPCM by
                        fitting model to stacked data
item.gpcm               Estimates item parameters of LMA with linear
                        restrictions on category scores
iterationPlot           Plots estimated parameters by iteration for the
                        gpcm and nominal models
lma.summary             Produces a summary of results
ple.lma                 Main function for estimating parameters of LMA
                        models
reScaleItem             Re-scales the category scale values and Phi
                        after convergence of the nominal model
scalingPlot             Graphs estimated scale values by integers of
                        the LMA (nominal) model
set.up                  Sets up the data based on input data and model
                        specifications
theta.estimates         Computes estimates of theta (values on latent
                        trait(s)) for all LMA models
vocab                   Dataframe of response to vocabulary items from
                        the 2018 General Social Survey
