View source: R/person.parameter.R
person.parameter | R Documentation |
Maximum likelihood estimation of the person parameters with spline interpolation for non-observed and 0/full responses. Extraction of information criteria such as AIC, BIC, and cAIC based on unconditional log-likelihood.
## S3 method for class 'eRm'
person.parameter(object)
## S3 method for class 'ppar'
summary(object, ...)
## S3 method for class 'ppar'
print(x, ...)
## S3 method for class 'ppar'
plot(x, xlab = "Person Raw Scores",
ylab = "Person Parameters (Theta)", main = NULL, ...)
## S3 method for class 'ppar'
coef(object, extrapolated = TRUE, ...)
## S3 method for class 'ppar'
logLik(object, ...)
## S3 method for class 'ppar'
confint(object, parm, level = 0.95, ...)
object |
Object of class |
Arguments for print
and plot
methods:
x |
Object of class |
xlab |
Label of the x-axis. |
ylab |
Label of the y-axis. |
main |
Title of the plot. |
... |
Further arguments to be passed to or from other methods. They are ignored in this function. |
Arguments for the coef
method:
extrapolated |
either returns extrapolated values for raw scores 0 and k or sets them |
Arguments for confint
:
parm |
Parameter specification (ignored). |
level |
Alpha-level. |
If the data set contains missing values, person parameters are estimated for each missing value subgroup.
The function person.parameter
returns an object of class ppar
containing:
loglik |
Log-likelihood of the collapsed data (for faster estimation persons with the same raw score are collapsed). |
npar |
Number of parameters. |
niter |
Number of iterations. |
thetapar |
Person parameter estimates. |
se.theta |
Standard errors of the person parameters. |
hessian |
Hessian matrix. |
theta.table |
Matrix with person parameters (ordered according to original data) including NA pattern group. |
pers.ex |
Indices with persons excluded due to 0/full raw score |
X.ex |
Data matrix with persons excluded |
gmemb |
NA group membership vector (0/full persons excluded) |
The function coef
returns a vector of the person parameter estimates for each person (i.e., the first column
of theta.table
).
The function logLik
returns an object of class loglik.ppar
containing:
loglik |
Log-likelihood of the collapsed data (see above). |
df |
Degrees of freedom. |
Patrick Mair, Reinhold Hatzinger
Fischer, G. H., and Molenaar, I. (1995). Rasch Models - Foundations, Recent Developements, and Applications. Springer.
Mair, P., and Hatzinger, R. (2007). Extended Rasch modeling: The eRm package for the application of IRT models in R. Journal of Statistical Software, 20(9), 1-20.
Mair, P., and Hatzinger, R. (2007). CML based estimation of extended Rasch models with the eRm package in R. Psychology Science, 49, 26-43.
itemfit.ppar
,personfit.ppar
#Person parameter estimation of a rating scale model
res <- RSM(rsmdat)
pres <- person.parameter(res)
pres
summary(pres)
plot(pres)
#Person parameter estimation for a Rasch model with missing values
res <- RM(raschdat2, se = FALSE) #Rasch model without standard errors
pres <- person.parameter(res)
pres #person parameters
summary(pres)
logLik(pres) #log-likelihood of person parameter estimation
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