# IMS Global QTI Glossary of Terms for Usage Data Distractor Statistics

## Vocabulary Details

This document provides a human readable description of the vocabulary terms defined in the IMS Global Vocabulary Definition and Exchange (VDEX) file "distractorstatisticsglossaryv1p0.xml". The details of the vocabulary are:

Vocabulary Identifier: | http://www.imsglobal.org/qti/qtiv2p1/distractorstatisticsglossaryv1p0
Vocabulary Type: | glossaryOrDictionary
Registered Status: | true
Vocabulary Language: | en-US
Author: | Colin Smythe, IMS Global (UK)
Issue Date: | 2013-01-07
Version: | 1.0
Status: | Final Release
Base Specification: | Question and Test Interoperability (QTI) Version 2.1
Keywords: | QTIv2.1, Usage Data, Distractor Statistics Glossary
Publisher: | IMS Global Learning Consortium Inc.
Copyright: | 2012 (c) IMS Global Learning Consortium Inc.
Description: | The set of terms that would be used to collect distractor statistics. This is the value that will be entered in the 'name' element.
History: | Version 1.0: The first formal release of this QTI Glossary.
License: | Users of products or services that include this document are hereby granted a worldwide, royalty-free, non-exclusive license to use this document.

## Vocabulary Terms

The set of terms for the vocabulary are described in the table below.

Identifier | Caption | Description
--- | --- | ---
AISResponse | Average Item Score for Response | Equal to the mean of the item scores for the group of indviduals that selected the response option.
NumberChoosingResponse | The number of people choosing a specified response or getting a specified code. | Equal to the number of individuals that selected the response option. This can also be used for the number of individuals that received a certain rating on a judged item such as an essay question.
PTbis-Response | r-pointbiserial for Response | A group-dependent measure of the discrimination of the response option, the pointbiserial correlation between selection of the response option and a criterion such as the total score on the test.
ParentChoosingResponse | The percent of people choosing a specified response or getting a specified code. | Equal to the percent of test takers that selected the response option. This can also be used for the percent of indviduals that received a certain rating on a judged item such as an essay question.