Extract model coefficients from an object of "difORD" class.

S3 method for extracting estimated model coefficients from an object of "difORD" class.

Usage

# S3 method for class 'difORD'
coef(object, SE = FALSE, simplify = FALSE, IRTpars = TRUE, CI = 0.95, ...)

Arguments

object

an object of "difORD" class.

SE

logical: should the standard errors of estimated parameters be also returned? (default is FALSE).

simplify

logical: should the estimated parameters be simplified to a matrix? (default is FALSE).

IRTpars

logical: should the estimated parameters be returned in IRT parameterization? (default is TRUE).

CI

numeric: level of confidence interval for parameters, default is 0.95 for 95% confidence interval.

...

other generic parameters for coef() function.

See also

difORD for DIF detection among ordinal data.
coef for generic function extracting model coefficients.

Author

Adela Hladka (nee Drabinova)
Institute of Computer Science of the Czech Academy of Sciences
Faculty of Mathematics and Physics, Charles University
hladka@cs.cas.cz

Patricia Martinkova
Institute of Computer Science of the Czech Academy of Sciences
martinkova@cs.cas.cz

Examples

if (FALSE) { # \dontrun{
# loading data
data(Anxiety, package = "ShinyItemAnalysis")
Data <- Anxiety[, paste0("R", 1:29)] # items
group <- Anxiety[, "gender"] # group membership variable

# testing both DIF effects with adjacent category logit model
(x <- difORD(Data, group, focal.name = 1, model = "adjacent"))

# estimated parameters
coef(x)
# includes standard errors
coef(x, SE = TRUE)
# includes standard errors and simplifies to matrix
coef(x, SE = TRUE, simplify = TRUE)
# intercept-slope parameterization
coef(x, IRTpars = FALSE)
# intercept-slope parameterization, simplifies to matrix, turn off confidence intervals
coef(x, IRTpars = FALSE, simplify = TRUE, CI = 0)
} # }