coef-method: Extract raw coefs from model object

In mirt: Multidimensional Item Response Theory

Extract raw coefs from model object

Description

Return a list (or data.frame) of raw item and group level coefficients. Note that while the output to the console is rounded to three digits, the returned list of objects is not. Hence, elements from cfs <- coef(mod); cfs[[1]] will contain the non-rounded results (useful for simulations).

Usage

## S4 method for signature 'SingleGroupClass'
coef(
  object,
  CI = 0.95,
  printSE = FALSE,
  rotate = "none",
  Target = NULL,
  IRTpars = FALSE,
  rawug = FALSE,
  as.data.frame = FALSE,
  simplify = FALSE,
  unique = FALSE,
  verbose = TRUE,
  ...
)

Arguments

object	an object of class SingleGroupClass, MultipleGroupClass, or MixedClass
CI	the amount of converged used to compute confidence intervals; default is 95 percent confidence intervals
printSE	logical; print the standard errors instead of the confidence intervals? When IRTpars = TRUE then the delta method will be used to compute the associated standard errors from mirt's default slope-intercept form
rotate	see summary method for details. The default rotation is 'none'
Target	a dummy variable matrix indicting a target rotation pattern
IRTpars	logical; convert slope intercept parameters into traditional IRT parameters? Only applicable to unidimensional models or models with simple structure (i.e., only one non-zero slope). If a suitable ACOV estimate was computed in the fitted model, and printSE = FALSE, then suitable CIs will be included based on the delta method (where applicable)
rawug	logical; return the untransformed internal g and u parameters? If FALSE, g and u's are converted with the original format along with delta standard errors
as.data.frame	logical; convert list output to a data.frame instead?
simplify	logical; if all items have the same parameter names (indicating they are of the same class) then they are collapsed to a matrix, and a list of length 2 is returned containing a matrix of item parameters and group-level estimates
unique	return the vector of uniquely estimated parameters
verbose	logical; allow information to be printed to the console?
...	additional arguments to be passed

References

Chalmers, R., P. (2012). mirt: A Multidimensional Item Response Theory Package for the R Environment. Journal of Statistical Software, 48(6), 1-29. \Sexpr[results=rd]{tools:::Rd_expr_doi("10.18637/jss.v048.i06")}

See Also

summary-method

Examples

## Not run: 
dat <- expand.table(LSAT7)
x <- mirt(dat, 1)
coef(x)
coef(x, IRTpars = TRUE)
coef(x, simplify = TRUE)

#with computed information matrix
x <- mirt(dat, 1, SE = TRUE)
coef(x)
coef(x, printSE = TRUE)
coef(x, as.data.frame = TRUE)

#two factors
x2 <- mirt(Science, 2)
coef(x2)
coef(x2, rotate = 'varimax')


## End(Not run)

mirt documentation built on Sept. 11, 2024, 7:14 p.m.