# Item Response Theory and Computerized Adaptive Testing Functions

## Documentation for package ‘irt’ version 0.2.7

- DESCRIPTION file.
- User guides, package vignettes and other documentation.

## Help Pages

A B C D E G I K L M P Q R S T V misc

## -- A --

add_misc | Add or change a named value to 'misc' slot of an 'Item-class', 'Itempool-class' or 'Testlet-class' object.
add_misc-method | Add or change a named value to 'misc' slot of an 'Item-class', 'Itempool-class' or 'Testlet-class' object.
area_between_icc | Calculate the area between two ICC curves
as.data.frame.cat_output | Convert a 'cat_output' object into a 'data.frame'.
as.data.frame.GPCM | Convert an 'Item-class' object into a 'data.frame'.
as.data.frame.GPCM2 | Convert an 'Item-class' object into a 'data.frame'.
as.data.frame.GRM | Convert an 'Item-class' object into a 'data.frame'.
as.data.frame.Item | Convert an 'Item-class' object into a 'data.frame'.
as.data.frame.Itempool | Convert an 'Item-class' object into a 'data.frame'.
as.data.frame.M2PL | Convert an 'Item-class' object into a 'data.frame'.
as.data.frame.M3PL | Convert an 'Item-class' object into a 'data.frame'.
as.data.frame.PCM | Convert an 'Item-class' object into a 'data.frame'.
as.data.frame.Response | Convert a 'Response-class' object into a 'data.frame'.
as.data.frame.Response_set | Convert a 'Response_set-class' object into a long format 'data.frame'
as.data.frame.Testlet | Convert an 'Item-class' object into a 'data.frame'.
as.Itempool | Coerce a given object to 'Itempool-class' object
as.list.Itempool | This function converts Itempool objects to a list object
as.list.Response_set | This function converts Response_set objects to a list object
as.matrix-method | Convert a 'Response_set-class' object into a 'matrix'

## -- B --

biserial | Calculate biserial correlation

## -- C --

c-method | Concatenate 'Item', 'Itempool' or 'Testlet' objects and return an Itempool object.
c.cat_design | Concatenate 'cat_design' objects
calculate_exposure_rates | Calculate exposure rate of items for CAT
calculate_overlap_rates | Calculate overlap rate of items for CAT
cat_sim | Computerized Adaptive Test (CAT) Simulation
cat_sim_fast | Computerized Adaptive Test (CAT) Simulation (Parallel Computing)
classification_agreement_index | Calculate agreement index
classification_indices | Calculate classification accuracy and consistency
create_cat_design | Computerized Adaptive Test (CAT) Simulation Design
cusum_single | CUSUM based statistics for one examinee

## -- D --

dif | Evaluate Differential Item Functioning (DIF) of a test
distractor_analysis | Distractor Analysis Function

## -- E --

est_ability | Estimate Ability of Examinees
est_bilog | Item Calibration via BILOG-MG
est_flexmirt | Unidimensional Item Calibration via flexMIRT

## -- G --

generate_ip | Generate a random 'Itempool' object
generate_item | Generate a random Item object
generate_resp | Generate random item responses (Response object)
generate_resp_set | Generate a random item responses (Response_set object)
generate_testlet | Generate a random Testlet object
get_cat_administered_items | Get administered items from a CAT output
get_cat_response_data | Extracts the response data of CAT output.
get_max_possible_total_score | Calculate the maximum score of a set of items
GPCM-class | Generalized Partial Credit Model
GPCM2-class | Reparameterized Generalized Partial Credit Model
GRM-class | Graded Response Model

## -- I --

info | Calculates the information of an "Item" object
info-method | Calculates the information of an "Item" object
ipd | Item Parameter Drift
irt | A Collection of Item Response Theory (IRT) and Computerized Adaptive Testing (CAT) Functions
is.Item | Check whether an object is an 'Item-class'
is.Itempool | Check whether an object is an 'Item-class'
is.Testlet | Check whether an object is an 'Item-class'
item | Create an 'Item' object
Item-class | An S4 class to represent an Item
itempool | Create an 'Itempool' object
Itempool-class | An S4 class to represent an Itempool
item_analysis | Item Analysis Function
item_fit | Calculate item-fit indices

## -- K --

ks | Item Characteristic Curve Estimation using Kernel Smoothing

## -- L --

length-method | Find the length of an 'Itempool-class' object

## -- M --

M2PL-class | Multidimensional Two-Parameter Logistic Model
M3PL-class | Multidimensional Three-Parameter Logistic Model
max_score | Calculate the maximum possible score
max_score-method | Calculate the maximum possible score
mean-method | Calculate the expected value of an Item
mean-method | Calculate the expected value of an Itempool
mean-method | Calculate the expected value of an Testlet

## -- P --

PCM-class | Partial Credit Model
person_fit | Calculate person-fit indices
person_fit-method | Calculate person-fit indices
plot.cat_output | Plot progress of a CAT algorithm for one examinee
plot.Item | Plot Item Characteristic Curve of an 'Item' object
plot.Itempool | Plot Item Characteristic Curves or Test Characteristic Curve of an 'Itempool' object
plot.ks_output | Plot Item Fit using Kernel-Smoothing
plot_distractor_icc | Plot Empirical Item or Test characteristic curve
plot_empirical_icc | Plot Empirical Item characteristic curve
plot_empirical_icc2 | Plot Empirical Item Characteristic Curve
plot_info | Plot Item Information Function
plot_resp_loglik | Plot the Log-Likelihood of a response string
prob | Calculate the probability of a correct response
prob-method | Calculate the probability of a correct response
prob_sum_score | Calculate summed-score probabilities

## -- Q --

qip_index | Calculate Quality of Item Pool Index

## -- R --

Rasch-class | Rasch model
response | Create a Response object from a vector of responses
Response-class | An S4 class representing responses of a single examinee
response_set | Create 'Response_set-class' object
Response_set-class | An S4 class representing responses of a set of examinees
resp_lik | Likelihood of a response string
resp_lik-method | Likelihood of a response string
resp_loglik | Log-likelihood of a Response String
resp_loglik-method | Log-likelihood of a Response String
rsss | Convert raw score to scale score and vice versa

## -- S --

score_info | Calculate Score Information Function
sim_resp | Generate responses for a given model
sim_resp-method | Generate responses for a given model
summary.cat_output | Summarizes the raw output of cat_sim

## -- T --

testlet | Creates a 'Testlet-class' object
Testlet-class | An S4 class to represent a Testlet

## -- V --

var-method | Calculate the variance of an Item
var-method | Calculate the variances of items in an Itempool
var-method | Calculate the variances of items in a Testlet

## -- misc --

$-method | Get slots from an 'Item-class' object.
$-method | Get slots of the an 'Itempool-class' object.
$-method | Get slots of the an 'Response-class' object.
$-method | Get slots of the a 'Response_set-class' object.
$-method | Access slots of a 'Testlet-class' object
$.cat_output | Prints the raw output of cat_sim
$<--method | Set values to parameters or components of 'Item-class' object
$<--method | Set values to parameters or components of 'Itempool' class.
$<--method | Set values to components of 'Response' class objects
$<--method | Set values to components of 'Response_set' class objects
$<--method | Set values to parameters or components of 'Testlet-class' object
1PL-class | One-Parameter Logistic IRT model
2PL-class | Two-Parameter Logistic IRT model
3PL-class | Three-Parameter Logistic IRT model
4PL-class | Three-Parameter Logistic IRT model