Checks if model is a null-model (intercept-only), i.e. if the conditional part of the model has no predictors.
Examples
model <- lm(mpg ~ 1, data = mtcars)
is_nullmodel(model)
#> [1] TRUE
model <- lm(mpg ~ gear, data = mtcars)
is_nullmodel(model)
#> [1] FALSE
if (require("lme4")) {
model <- lmer(Reaction ~ 1 + (Days | Subject), data = sleepstudy)
is_nullmodel(model)
model <- lmer(Reaction ~ Days + (Days | Subject), data = sleepstudy)
is_nullmodel(model)
}
#> [1] FALSE