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Cronbach's Alpha for Items or Scales

Source: R/cronbachs_alpha.R
cronbachs_alpha.Rd

Compute various measures of internal consistencies for tests or item-scales of questionnaires. cronbachs_alpha() calculates the Cronbach's Alpha value for all variables in x. item_alpha() is an alias for cronbachs_alpha().

Usage

cronbachs_alpha(x, ...)

item_alpha(x, ...)

# S3 method for class 'data.frame'
cronbachs_alpha(x, verbose = TRUE, ...)

Arguments

x

A matrix or a data frame, or an object of class parameters_pca, as returned by parameters::principal_components(), or an object of class parameters_efa, as returned by parameters::factor_analysis().

...

Currently not used.

verbose

Toggle warnings and messages.

Value

The Cronbach's Alpha value for x.

Details

The Cronbach's Alpha value for x. A value closer to 1 indicates greater internal consistency, where usually following rule of thumb is applied to interpret the results:

  • α < 0.5 is unacceptable,

  • 0.5 < α < 0.6 is poor,

  • 0.6 < α < 0.7 is questionable,

  • 0.7 < α < 0.8 is acceptable,

  • and everything > 0.8 is good or excellent.

Note

item_alpha() is an alias for cronbachs_alpha().

References

Bland, J. M., and Altman, D. G. Statistics notes: Cronbach's alpha. BMJ 1997;314:572. 10.1136/bmj.314.7080.572

Examples

data(mtcars)
x <- mtcars[, c("cyl", "gear", "carb", "hp")]
cronbachs_alpha(x)
#> [1] 0.09463206