Last data update: 2014.03.03
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R: Area under the Test or Item Information Curves
information | R Documentation |
Area under the Test or Item Information Curves
Description
Computes the amount of test or item information for a fitted IRT model, in a specified range.
Usage
information(object, range, items = NULL, ...)
Arguments
object |
an object inheriting from either class gpcm , class grm , class ltm , class rasch or class tpm .
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range |
a numeric interval for which the test information should be computed.
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items |
the items for which the information should be computed; the default NULL corresponds
to all the items, which is equivalent to the test information.
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... |
extra arguments passed to integrate() .
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Details
The amount of information is computed as the area under the Item or Test Information Curve in the specified
interval, using integrate() .
Value
A list of class information with components,
InfoRange |
the amount of information in the specified interval.
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InfoTotal |
the total amount of information; typically this is computed as the amount of information
in the interval (-10, 10).
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PropRange |
the proportion of information in the specified range, i.e.,
"Info in range" / "Total Info" .
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range |
the value of range argument.
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items |
the value of items argument.
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call |
the matched call for object .
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Author(s)
Dimitris Rizopoulos d.rizopoulos@erasmusmc.nl
See Also
plot.gpcm ,
plot.grm ,
plot.ltm ,
plot.rasch
Examples
fit <- rasch(LSAT)
information(fit, c(-2, 0))
information(fit, c(0, 2), items = c(3, 5))
Results
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