information {ltm} | R Documentation |
Computes the amount of test or item information for a fitted IRT model, in a specified range.
information(object, range, items = NULL, ...)
object |
an object inheriting from either class grm , class ltm , class rasch or class tpm . |
range |
a numeric interval for which the test information should be computed. |
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. |
... |
extra arguments passed to integrate() . |
The amount of information is computed as the area under the Item or Test Information Curve in the specified
interval, using integrate()
.
A list with components,
Info in range |
the amount of information in the specified interval. |
Total Info |
the total amount of information; typically this is computed as the amount of information in the interval (-10, 10). |
Proportion in range |
the proportion of information in the specified range, i.e.,
"Info in range" / "Total Info" . |
Dimitris Rizopoulos dimitris.rizopoulos@med.kuleuven.be
plot.grm
,
plot.ltm
,
plot.rasch
m <- rasch(Lsat) information(m, c(-2, 0)) information(m, c(0, 2), items = c(3, 5))