plotGR: Plot Treatment or Covariate Effects for LLRA

In eRm: Extended Rasch Modeling

Plot Treatment or Covariate Effects for LLRA

Description

Plots treatment or covariate group effects over time.

Usage

plotGR(object, ...)

Arguments

object	an object of class "llra".
...	Additional parameters to be passed to and from other methods.

Details

The plot is a lattice plot with each panel corresponding to an item. The effects are plotted for each groups (including baseline) over the different time points. The groups are given the same names as for the parameter estimates (derived from groupvec).

Please note that all effects are to be interpreted relative to the baseline.

Currently, this function only works for a full item x treatment x timepoints LLRA. Collapsed effects will not be displayed properly.

Warning:

Objects of class "llra" that contain estimates from a collapsed data matrix will not be displayed correctly.

Author(s)

Thomas Rusch

See Also

The plot method for trend effects plotTR.

Examples

##Example 6 from Hatzinger & Rusch (2009)
groups <- c(rep("TG",30),rep("CG",30))
llra1 <- LLRA(llradat3,mpoints=2,groups=groups)
summary(llra1)
plotGR(llra1)

## Not run:   
##An LLRA with 2 treatment groups and 1 baseline group, 5 items and 4
##time points. Item 1 is dichotomous, all others have 3, 4, 5, 6
##categories respectively.
ex2 <- LLRA(llraDat2[1:20],mpoints=4,groups=llraDat2[21])
plotGR(ex2)
## End(Not run)

eRm documentation built on May 29, 2024, 2:12 a.m.