AssessmentItem:Item Body

The QTI specification states that

“The item body contains the text, graphics, media objects and interactions that describe the item's content and information about how it is structured.”

In other words, this section specifies

1. the item as seen on screen by the candidate e.g. Moreover, this section records the names of the multimedia files (such as sound and video clips) which these components may use.
 * the introductory rubric
 * the stem
 * options
 * feedback
 * hints

2.interaction(s) between the candidate and the item. The specification states that

''“Interactions allow the candidate to interact with the item. Through an interaction, the candidate selects or constructs a response. The candidate's responses are stored in the responseVariables. Each interaction is associated with (at least) one response variable.”''

An interaction may be thought of as a “dialogue” between the candidate and the running item. The candidate is prompted for or constructs a response, submits that response (e.g. via a button on screen) and there is some perceptible feedback from the system to the candidate. Several interactions may occur within one execution of an item.

Interactions therefore involve response variables and response processing logic.

Internal Structure of ItemBody
An ItemBody element comprises one or more block elements. There are four types of block, as show in the second level of the diagram below.


 * blockInteraction is the most commonly used block type. It implements familiar interaction types such as multiple choice, matching gaps and slider bars.
 * blockStatic blocks do not support interactions – rather they specify visual components such as text, pictures and tables
 * customInteraction blocks allow you to extend the specification and build your own new interaction types
 * positionObjectStage blocks support images onto which the candidate can place other visual objects

Block Interaction Examples
There are eleven types of blockInteraction element. Let’s examine a couple in detail – choiceInteraction and matchInteraction.

Example 1 – choiceInteraction
The following example item (“Unattended Luggage”) comes from the QTI specification:-



 Look at the text in the picture.   What does it say? You must stay with your luggage at all times. Do not let someone else look after your luggage. Remember your luggage when you leave.  

This ItemBody contains three blocks

If the candidate were to select the second option (i.e. “Do not let someone else look 	after your luggage”), then the response variable RESPONSE would be set to the value 	“ChoiceB”.
 * two blocks which begin  (i.e. a blockStatic block - see above diagram)
 * the first contains introductory text
 * the second contains a reference to an external image file
 * one choiceInteraction block – this employs a response variable called RESPONSE. It also specifies two block attributes – shuffle and maxChoices – which are directives to the delivery engine processing the item.  The block then issues a prompt to the candidate and presents three options, each of which specifies
 * an internal identifier (e.g. ChoiceB), which is hidden from the candidate
 * text which is visible to the candidate

Where does the item store the correct answer of the question? It appears earlier in the item xml, where the response variable RESPONSE is declared – incorporating the correctResponse element.

  ChoiceA  

Example 2 – matchInteraction
The following example item (“Characters and Plays”) comes from the QTI specification:-



This example employs a matchInteraction block within ItemBody. First let’s look at its item variables   C R    D M     L M     P T   </correctResponse> <mapping defaultValue="0"> <mapEntry mapKey="C R" mappedValue="1" /> <mapEntry mapKey="D M" mappedValue="0.5" /> <mapEntry mapKey="L M" mappedValue="0.5" /> <mapEntry mapKey="P T" mappedValue="1" /> </responseDeclaration> <outcomeDeclaration identifier="SCORE" cardinality="single" baseType="float" /> The response variable RESPONSE does not hold one value; instead it stores one or more pairs of values. The latter are input by the candidate.

The correct answer is stored as four pairs (see correctResponse element above).

The mapping element assigns a value to any correct combination (e.g. “C R”) entered by the candidate.

There is also an outcome variable called SCORE declared in the item.

The ItemBody contains the matchInteraction block. The latter specifies two internal simpleMatchSet elements, each of which describes a list of values. The matchMax attributes places an upper limit of how many associations can be specified against a particular value in a list.  <matchInteraction responseIdentifier="RESPONSE" shuffle="true" maxAssociations="4"> Match the following characters to the Shakespeare play they appeared in: <simpleMatchSet> <simpleAssociableChoice identifier="C" matchMax="1">Capulet</simpleAssociableChoice> <simpleAssociableChoice identifier="D" matchMax="1">Demetrius</simpleAssociableChoice> <simpleAssociableChoice identifier="L" matchMax="1">Lysander</simpleAssociableChoice> <simpleAssociableChoice identifier="P" matchMax="1">Prospero</simpleAssociableChoice> </simpleMatchSet> <simpleMatchSet> <simpleAssociableChoice identifier="M" matchMax="4">A Midsummer-Night's Dream</simpleAssociableChoice> <simpleAssociableChoice identifier="R" matchMax="4">Romeo and 	Juliet</simpleAssociableChoice> <simpleAssociableChoice identifier="T" matchMax="4">The Tempest</simpleAssociableChoice> </simpleMatchSet> </matchInteraction> </itemBody>