R package lsmeans: Least-squares means (predicted marginal means)

Features

• For an overview, see the vignette -- also available via vignette("using-lsmeans", package = "lsmeans")
• Least-squares means (a.k.a. predicted marginal means) are derived by using a model to make predictions over a regular grid of pridictor combinations (called a reference grid). These predictions may possibly be averaged (typically with equal weights) over one or more of the predictors. Such marginally-averaged predictions are useful for describing the results of fitting a model, particularly in presenting the effects of factors. The lsmeans package can easily produce these results, as well as various graphs of them (interaction-style plots and side-by-side intervals).
• Estimation and testing of pairwise comparisons of LS means, and several other types of contrasts, are provided. There is also a cld method for display of grouping symbols.
• Two-way support of the glht function in the multcomp package.
• For models where continuous predictors interact with factors, the package's lstrends function works in terms of a reference grid of predicted slopes of trend lines for each factor combination.
• Incorporates support for many types of models, including those in stats package (lm, glm, aov, aovlist), linear and genearalized linear mixed models (e.g., nlme, lme4, afex), ordinal-response models (e.g., ordinal, MASS), survival analysis (e.g., survival, coxme), generalized estimating equations (gee, geepack), and others. See help("models"", package="lsmeans")
• Various Bayesian models (carBayes, MCMCglmm, MCMCpack) are supported by way of creating a posterior sample of least-squares means or contrasts thereof, which may then be examined using tools such as in the coda package.
• Package developers may provide lsmeans support for their models by providing recover.data and lsm.basis methods. See vignette("extending", package = "lsmeans")

Installation

• To install latest version from CRAN, run

install.packages("lsmeans")

Release notes for the latest CRAN version are found at https://CRAN.R-project.org/package=lsmeans/NEWS -- or do news(package = "lsmeans") for notes on the version you have installed.

• To install the latest development version from Github, have the newest devtools package installed, then run

devtools::install_github("rvlenth/lsmeans", dependencies = TRUE)

For latest release notes on this development version, see the NEWS file