com.itemanalysis.psychometrics.irt.model

Class AbstractItemResponseModelWithGradient

java.lang.Object

com.itemanalysis.psychometrics.irt.model.AbstractItemResponseModelWithGradient

All Implemented Interfaces:

ItemResponseModel

Direct Known Subclasses:

Irm3PL

public abstract class AbstractItemResponseModelWithGradient
extends java.lang.Object
implements ItemResponseModel

Field Summary

Fields

Modifier and Type	Field and Description
protected java.lang.String	groupId
protected boolean	isFixed
protected int	maxCategory
protected double	maxWeight
protected int	minCategory
protected double	minWeight
protected VariableName	name
protected int	ncat
protected double[]	scoreWeight

Constructor Summary

Constructors

Constructor and Description
AbstractItemResponseModelWithGradient()

Method Summary

Modifier and Type	Method and Description
protected void	defaultScoreWeights()
java.lang.String	getGroupId() Gets the item group ID code.
ItemFitStatistic	getItemFitStatistic()
ItemScoring	getItemScoring()
double	getMaxScoreWeight() Gets the largest possible score weight.
double	getMinScoreWeight() Gets the lowest possible score weight.
VariableName	getName() Gets the name of the item.
int	getNcat() Gets the number of response categories.
byte[]	getScoreWeights() Gets an array fo score weights.
boolean	isFixed() A fixed item will use its initial values as the item parameters and no further estimation or update will be applied to the item parameters.
void	setFixed(boolean isFixed) If parameters can be estimated, the isFixed should be false.
void	setGroupId(java.lang.String groupId) An item may be assigned to a group of items.
void	setItemFitStatistic(ItemFitStatistic itemFitStatistic)
void	setItemScoring(ItemScoring itemScoring)
void	setName(VariableName name) Sets the name of the item.
void	setScoreWeights(double[] scoreWeight) A polytomous item is scored with two or more ordinal categories such as 0, 1, 2, 3 or 1, 2, 3, 4, 5.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.itemanalysis.psychometrics.irt.model.ItemResponseModel

acceptAllProposalValues, addPriorsToLogLikelihood, addPriorsToLogLikelihoodGradient, cumulativeProbability, derivTheta, expectedValue, getDifficulty, getDifficultyStdError, getDiscrimination, getDiscriminationStdError, getGuessing, getGuessingStdError, getItemParameterArray, getNumberOfEstimatedParameters, getNumberOfParameters, getProposalDifficulty, getScalingConstant, getSlipping, getSlippingStdError, getStepParameters, getStepStdError, getThresholdParameters, getThresholdStdError, getType, gradient, gradient, incrementMeanMean, incrementMeanSigma, itemInformationAt, nonZeroPrior, probability, probability, scale, setDifficulty, setDifficultyPrior, setDifficultyStdError, setDiscrimination, setDiscriminationPrior, setDiscriminationStdError, setGuessing, setGuessingPrior, setGuessingStdError, setProposalDifficulty, setProposalDiscrimination, setProposalGuessing, setProposalSlipping, setProposalStepParameters, setProposalThresholds, setSlipping, setSlippingPrior, setSlippingStdError, setStandardErrors, setStepParameters, setStepPriorAt, setStepStdError, setThresholdParameters, setThresholdStdError, tSharpExpectedValue, tSharpProbability, tStarExpectedValue, tStarProbability

Field Detail

groupId

protected java.lang.String groupId

name

protected VariableName name

scoreWeight

protected double[] scoreWeight

ncat

protected int ncat

minCategory

protected int minCategory

maxCategory

protected int maxCategory

isFixed

protected boolean isFixed

minWeight

protected double minWeight

maxWeight

protected double maxWeight

Constructor Detail

AbstractItemResponseModelWithGradient

public AbstractItemResponseModelWithGradient()

Method Detail

setName

public void setName(VariableName name)

Description copied from interface: ItemResponseModel

Sets the name of the item.

Specified by:

setName in interface ItemResponseModel

Parameters:

name - an item name

getName

public VariableName getName()

Description copied from interface: ItemResponseModel

Gets the name of the item.

Specified by:

getName in interface ItemResponseModel

Returns:

item name.

setGroupId

public void setGroupId(java.lang.String groupId)

Description copied from interface: ItemResponseModel

An item may be assigned to a group of items. The group membership code is the group ID. This method sets the groupId for this item.

Specified by:

setGroupId in interface ItemResponseModel

Parameters:

groupId - the group ID.

getGroupId

public java.lang.String getGroupId()

Description copied from interface: ItemResponseModel

Gets the item group ID code.

Specified by:

getGroupId in interface ItemResponseModel

Returns:

item group ID.

getNcat

public int getNcat()

Description copied from interface: ItemResponseModel

Gets the number of response categories. This value is 2 for binary items and greater than 2 for polytomous items.

Specified by:

getNcat in interface ItemResponseModel

Returns:

number of response categories.

setItemFitStatistic

public void setItemFitStatistic(ItemFitStatistic itemFitStatistic)

Specified by:

setItemFitStatistic in interface ItemResponseModel

getItemFitStatistic

public ItemFitStatistic getItemFitStatistic()

Specified by:

getItemFitStatistic in interface ItemResponseModel

isFixed

public boolean isFixed()

Description copied from interface: ItemResponseModel

A fixed item will use its initial values as the item parameters and no further estimation or update will be applied to the item parameters. This method checks whether the item has been set as a fixed item.

Specified by:

isFixed in interface ItemResponseModel

Returns:

setFixed

public void setFixed(boolean isFixed)

If parameters can be estimated, the isFixed should be false. Setting isFixed to true prevents the item paramters from being estimated.

Specified by:

setFixed in interface ItemResponseModel

Parameters:

isFixed -

defaultScoreWeights

protected void defaultScoreWeights()

setScoreWeights

public void setScoreWeights(double[] scoreWeight)
                     throws org.apache.commons.math3.exception.DimensionMismatchException

Description copied from interface: ItemResponseModel

A polytomous item is scored with two or more ordinal categories such as 0, 1, 2, 3 or 1, 2, 3, 4, 5. The score weights are not the same as the array index of the threshold or step parameter estimates. They are weights applied to each category. The score weights are set with this method. If no score weights are set, then the default score wieghts are typically 0, 1, 2, and so on.

Specified by:

setScoreWeights in interface ItemResponseModel

Parameters:

scoreWeight - an array of category score weights.

Throws:

org.apache.commons.math3.exception.DimensionMismatchException

getMinScoreWeight

public double getMinScoreWeight()

Description copied from interface: ItemResponseModel

Gets the lowest possible score weight.

Specified by:

getMinScoreWeight in interface ItemResponseModel

Returns:

minimum score weight.

getMaxScoreWeight

public double getMaxScoreWeight()

Description copied from interface: ItemResponseModel

Gets the largest possible score weight.

Specified by:

getMaxScoreWeight in interface ItemResponseModel

Returns:

maximum score weight.

getScoreWeights

public byte[] getScoreWeights()

Description copied from interface: ItemResponseModel

Gets an array fo score weights.

Specified by:

getScoreWeights in interface ItemResponseModel

Returns:

setItemScoring

public void setItemScoring(ItemScoring itemScoring)

Specified by:

setItemScoring in interface ItemResponseModel

getItemScoring

public ItemScoring getItemScoring()

Specified by:

getItemScoring in interface ItemResponseModel