responseCurve: Produce data suitable for plotting item response curves
Description
Selects samples random draws from the posterior and evaluates the item
response curve on the grid given by seq(from,to,by).
All items use the same responseNames. If you have some items
with a different number of thresholds or different response names
then you can call responseCurve for each item separately
and rbind the results together.
Usage
responseCurve(
dl,
fit,
responseNames,
item = dl$nameInfo$item,
samples = 100,
from = qnorm(0.1),
to = -from,
by = 0.02
)
Value
A data.frame with the following columns:
response
Which response
worthDiff
Difference in worth
item
Which item
sample
Which sample
prob
Associated probability
responseSample
A grouping index for independent item response samples
Arguments
dl
a data list prepared by prepData
fit
a stanfit object
responseNames
a vector of labels for the possible responses
item
a vector of item names
samples
number of posterior samples
from
the starting latent difference value
to
the ending latent difference value
by
the grid increment
Response model
See cmp_probs for details.
See Also
Other data extractor:
parDistributionCustom(),
parInterval()