alldirec | R Documentation |
Calculates direct equating coefficients and standard errors using IRT methods between all pairs of a list of forms.
alldirec(mods, method = "mean-mean", all = FALSE, quadrature = TRUE, nq = 30, direction = "both")
mods |
an object of the class |
method |
the equating method to be used. This should be one of
" |
all |
logical; if FALSE forms that do not have common items will not appear in the output. |
quadrature |
logical; if TRUE the Gauss-Hermite quadrature is used to approximate the integral in the function that is minimized in the Haebara and Stocking-Lord methods. If FALSE the integral is replaced with a sum over 40 equally spaced values ranging from -4 to 4 with an increment of 0.05 and weights equal to one for all values. |
nq |
number of quadrature points used for the Gauss-Hermite quadrature
if |
direction |
a character string specifying the direction used to equate
pair of forms. If " |
An object of class eqclist
consisting in a list with length
equal to the number of pairs of forms equated. Each component of
the list is an object of class eqc
returned by function
direc
.
Michela Battauz
Battauz, M. (2015). equateIRT: An R Package for IRT Test Equating. Journal of Statistical Software, 68, 1–22.
Kolen, M.J. and Brennan, R.L. (2014). Test equating, scaling, and linking: methods and practices, 3rd ed., New York: Springer
Ogasawara, H. (2000). Asymptotic standard errors of IRT equating coefficients using moments. Economic Review (Otaru University of Commerce), 51, 1–23.
Ogasawara, H. (2001). Standard Errors of Item Response Theory Equating/Linking by Response Function Methods. Applied Psychological Measurement, 25, 53–67.
direc
, eqc
, itm
, modIRT
, summary.eqclist
# three-parameter logistic model # direct equating coefficients using the "Stocking-Lord" method data(est3pl) test <- paste("test", 1:5, sep = "") mod3pl <- modIRT(coef = est3pl$coef, var = est3pl$var, names = test, display = FALSE) direclist3pl <- alldirec(mods = mod3pl, method = "Stocking-Lord") summary(direclist3pl) summary(direclist3pl$test1.test2) # two-parameter logistic model # direct equating coefficients using the "Haebara" method data(est2pl) test <- paste("test", 1:5, sep = "") mod2pl <- modIRT(coef = est2pl$coef, var = est2pl$var, names = test, display = FALSE) direclist2pl <- alldirec(mods = mod2pl, method = "Haebara") summary(direclist2pl) summary(direclist2pl$test1.test5) # Rasch model # direct equating coefficients using the "mean-mean" method data(estrasch) test <- paste("test", 1:5, sep = "") modrasch <- modIRT(coef = estrasch$coef, var = estrasch$var, names = test, display = FALSE) direclistrasch <- alldirec(mods = modrasch, method = "mean-mean", all = TRUE) summary(direclistrasch) summary(direclistrasch$test5.test4)
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