bruceR: Alpha – R documentation

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Alpha

Reliability analysis (Cronbach's α and McDonald's ω).

Description

An extension of jmv::reliability(). It reports (1) scale reliability statistics (Cronbach's α and McDonald's ω) and (2) item reliability statistics (item-rest correlation [i.e., corrected item-total correlation] and what Cronbach's α and McDonald's ω would be if the item was dropped).

Three options to specify the variable list:

var + items: use the common and unique parts of variable names.
vars: directly define a variable list.
varrange: use the start and end positions of a variable list.

Usage

Alpha(data, var, items, vars = NULL, varrange = NULL, rev = NULL)

Arguments

`data`	Data frame.
`var`	[option 1] Common part across multiple variables (e.g., `"RSES", "SWLS"`).
`items`	[option 1] Unique part across multiple variables (e.g., `1:10`).
`vars`	[option 2] Character vector specifying a variable list (e.g., `c("E1", "E2", "E3", "E4", "E5")`).
`varrange`	[option 3] Character with `":"` specifying the start and end positions of a variable list (e.g., `"A1:E5"`).
`rev`	[optional] Reverse-scoring variables. It can be (1) a numeric vector specifying the positions of reverse-scoring variables (not recommended) or (2) a character vector directly specifying the variable list (recommended).

Value

A result object obtained from jmv::reliability().

Examples

# see ?psych::bfi
Alpha(bfi, "E", 1:5)  # "E1" & "E2" should be reverse scored
Alpha(bfi, "E", 1:5, rev=1:2)  # correct
Alpha(bfi, "E", 1:5, rev=c("E1", "E2"))  # also correct
Alpha(bfi, vars=c("E1", "E2", "E3", "E4", "E5"), rev=c("E1", "E2"))
Alpha(bfi, varrange="E1:E5", rev=c("E1", "E2"))

# using dplyr::select()
bfi %>% select(E1, E2, E3, E4, E5) %>%
  Alpha(vars=names(.), rev=c("E1", "E2"))

bruceR

Broadly Useful Convenient and Efficient R Functions

v0.6.2

GPL-3

Authors

Han-Wu-Shuang Bao [aut, cre]

Initial release

2021-04-08