group_mean_center: Group-mean centering.

In bruceR: Broadly Useful Convenient and Efficient R Functions

Group-mean centering.

Description

Compute group-mean centered variables. Usually used for HLM level-1 predictors.

Usage

group_mean_center(
  data,
  vars = setdiff(names(data), by),
  by,
  std = FALSE,
  add.suffix = "",
  add.group.mean = "_mean"
)

Arguments

data	Data object.
vars	Variable(s) to be centered.
by	Grouping variable.
std	Standardized or not. Defaults to FALSE.
add.suffix	The suffix of the centered variable(s). Defaults to "". You may set it to "_c", "_center", etc.
add.group.mean	The suffix of the variable name(s) of group means. Defaults to "_mean" (see Examples).

Value

A new data object containing the centered variable(s).

See Also

grand_mean_center()

Examples

d = data.table(x=1:9, g=rep(1:3, each=3))

d.c = group_mean_center(d, "x", by="g")
d.c

d.c = group_mean_center(d, "x", by="g", add.suffix="_c")
d.c

bruceR documentation built on Aug. 21, 2025, 5:38 p.m.