anova.lmerModLmerTest function

ANOVA Tables for Linear Mixed Models

ANOVA table with F-tests and p-values using Satterthwaite's or Kenward-Roger's method for denominator degrees-of-freedom and F-statistic. Models should be fitted with lmer from the lmerTest-package.

## S3 method for class 'lmerModLmerTest'
anova(
  object,
  ...,
  type = c("III", "II", "I", "3", "2", "1"),
  ddf = c("Satterthwaite", "Kenward-Roger", "lme4")
)

Arguments

• object: an lmerModLmerTest object; the result of lmer()

  after loading the lmerTest-package.

• ...: potentially additional lmer or lm model objects for comparison of models in which case type and ddf arguments are ignored.

• type: the type of ANOVA table requested (using SAS terminology) with Type I being the familiar sequential ANOVA table.

• ddf: the method for computing the denominator degrees of freedom and F-statistics. ddf="Satterthwaite" (default) uses Satterthwaite's method; ddf="Kenward-Roger" uses Kenward-Roger's method, ddf = "lme4" returns the lme4-anova table, i.e., using the anova method for lmerMod objects as defined in the lme4-package and ignores the type argument. Partial matching is allowed.

Returns

an ANOVA table

Details

The "Kenward-Roger" method calls pbkrtest::KRmodcomp internally and reports scaled F-statistics and associated denominator degrees-of-freedom.

Examples

data("sleepstudy", package="lme4")
m <- lmer(Reaction ~ Days + (Days | Subject), sleepstudy)
anova(m) # with p-values from F-tests using Satterthwaite's denominator df
anova(m, ddf="lme4") # no p-values

# Use the Kenward-Roger method
if(requireNamespace("pbkrtest", quietly = TRUE))
  anova(m, ddf="Kenward-Roger")

See Also

contestMD for multi degree-of-freedom contrast tests and KRmodcomp for the "Kenward-Roger" method.

Author(s)

Rune Haubo B. Christensen and Alexandra Kuznetsova