LSMEANS Statement
LSMEANS <model-effects> </ options> ;

The LSMEANS statement computes and compares least squares means (LS-means) of fixed effects. LS-means are predicted population margins—that is, they estimate the marginal means over a balanced population. In a sense, LS-means are to unbalanced designs as class and subclass arithmetic means are to balanced designs.

Table 39.3 summarizes important options in the LSMEANS statement. If you specify the BAYES statement, the ADJUST=, STEPDOWN, and LINES options are ignored. The PLOTS= option is not available for a maximum likelihood analysis; it is available only for a Bayesian analysis.

If you specify a zero-inflated model (that is, a model for either the zero-inflated Poisson or the zero-inflated negative binomial distribution), then the least squares means are computed only for effects in the model for the distribution mean, and not for effects in the zero-inflation probability part of the model.

Table 39.3 Important LSMEANS Statement Options

Option

Description

Construction and Computation of LS-Means

Modifies the covariate value in computing LS-means

Computes separate margins

Requests differences of LS-means

Specifies the weighting scheme for LS-means computation as determined by the input data set

SINGULAR=

Tunes estimability checking

Degrees of Freedom and p-values

Determines the method for multiple comparison adjustment of LS-means differences

ALPHA= Determines the confidence level ( )

Adjusts multiple comparison p-values further in a step-down fashion

Statistical Output

Constructs confidence limits for means and mean differences

Displays the correlation matrix of LS-means

Displays the covariance matrix of LS-means

Prints the matrix

Produces a "Lines" display for pairwise LS-means differences

Prints the LS-means

Requests ODS statistical graphics of means and mean comparisons

Specifies the seed for computations that depend on random numbers

Generalized Linear Modeling

Exponentiates and displays estimates of LS-means or LS-means differences

Computes and displays estimates and standard errors of LS-means (but not differences) on the inverse linked scale

ODDSRATIO

Reports (simple) differences of least squares means in terms of odds ratios if permitted by the link function

For details about the syntax of the LSMEANS statement, see the section LSMEANS Statement of Chapter 19, Shared Concepts and Topics.