gCD: Generalized Cook's Distance

Description

Compute generalize Cook's distances (gCD's) for exploratory and confirmatory FA. Can return DFBETA matrix if requested. If mirt is used, then the values will be associated with the unique response patterns instead.

Usage

gCD(data, model, vcov_drop = FALSE, progress = TRUE, ...)
# S3 method for gCD
print(x, ncases = 10, DFBETAS = FALSE, ...)
# S3 method for gCD
plot(
  x,
  y = NULL,
  main = "Generalized Cook Distance",
  type = c("p", "h"),
  ylab = "gCD",
  ...
)

Arguments

data: matrix or data.frame
model: if a single numeric number declares number of factors to extract in exploratory factor analysis (requires complete dataset, i.e., no missing). If class(model) is a sem (semmod), or lavaan (character), then a confirmatory approach is performed instead
vcov_drop: logical; should the variance-covariance matrix of the parameter estimates be based on the unique data[-i, ] models (Pek and MacCallum, 2011) or original data?
progress: logical; display the progress of the computations in the console?
...: additional parameters to be passed
x: an object of class gCD
ncases: number of extreme cases to display
DFBETAS: logical; return DFBETA matrix in addition to gCD? If TRUE, a list is returned
y: a NULL value ignored by the plotting function
main: the main title of the plot
type: type of plot to use, default displays points and lines
ylab: the y label of the plot

Author

Phil Chalmers rphilip.chalmers@gmail.com

Details

Note that gCD is not limited to confirmatory factor analysis and can apply to nearly any model being studied where detection of influential observations is important.

References

Chalmers, R. P. & Flora, D. B. (2015). faoutlier: An R Package for Detecting Influential Cases in Exploratory and Confirmatory Factor Analysis. Applied Psychological Measurement, 39, 573-574. tools:::Rd_expr_doi("10.1177/0146621615597894")

Flora, D. B., LaBrish, C. & Chalmers, R. P. (2012). Old and new ideas for data screening and assumption testing for exploratory and confirmatory factor analysis. Frontiers in Psychology, 3, 1-21. tools:::Rd_expr_doi("10.3389/fpsyg.2012.00055")