com.itemanalysis.psychometrics.irt.estimation

Class RaschScoreTable

java.lang.Object

com.itemanalysis.psychometrics.irt.estimation.RaschScoreTable

public class RaschScoreTable
extends java.lang.Object

A class for creating a raw to ablity score transformation table. It has its own estimation method. However, the estimation method is identical to JointMaximumLikelihoodEstimation.updatePerson(int, int, double, double).

Constructor Summary

Constructors

Constructor and Description
RaschScoreTable(ItemResponseModel[] irm, int[] extremeItem, int[] droppedStatus, int precision) The constructor should be called after joint maximum likelhood estimation is complete.

Method Summary

Modifier and Type	Method and Description
void	computePersonStandardErrors() Person ability parameter standard error calculation.
java.lang.Object[][]	getOutputArray()
void	linearTransformation(DefaultLinearTransformation lt, int precision) A linear transformation can be applied to teh score table.
java.lang.String	printScoreTable() The score table is formatted for output here.
void	updateScoreTable(int globalMaxIter, double globalConvergence, double adjustment) This method is the main entry point into the class.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

RaschScoreTable

public RaschScoreTable(ItemResponseModel[] irm,
                       int[] extremeItem,
                       int[] droppedStatus,
                       int precision)

The constructor should be called after joint maximum likelhood estimation is complete.

Parameters:

irm - an array of item resposne model objects.

extremeItem - an array of extreme item codes.

droppedStatus - an array of dropped item status codes. This argument is mainly needed for polytomous items.

Method Detail

updateScoreTable

public void updateScoreTable(int globalMaxIter,
                             double globalConvergence,
                             double adjustment)

This method is the main entry point into the class. It should be called soon after instantiation.

Parameters:

globalMaxIter - maximum number of iterations.

globalConvergence - convergence criterion.

adjustment - extreme score adjustment factor.

printScoreTable

public java.lang.String printScoreTable()

The score table is formatted for output here.

Returns:

score table.

linearTransformation

public void linearTransformation(DefaultLinearTransformation lt,
                                 int precision)

A linear transformation can be applied to teh score table. This method should be called after computePersonStandardErrors().

Parameters:

lt - linear transformation to be applied.

precision - number of decimal places to retain after the linear transformation.

computePersonStandardErrors

public void computePersonStandardErrors()

Person ability parameter standard error calculation.

getOutputArray

public java.lang.Object[][] getOutputArray()