User Experience Design Ontology: Base Vocabulary

Author(s): Coomans, Marc
Publisher: Agfa Healthcare
Date: 2011-11-04

Introduction

This document defines a User Experience Design ontology, a dictionary of named classes and properties using W3C's RDFa technology. The ontology can be used to annotate user interface design guidelines for IT products. Design guidelines in this field are extensive and varied. The initial goal of this ontology is to facilitate better search and filtering capabilities for these guidelines.

The URI of this ontology is: http://www.agfa.com/w3c/2009/uxd-1-0-base/. In the remainder of this document, we will assume that you import this vocabulary in your own document by associating the prefix "ux" with the above URI: xmlns:ux="http://www.agfa.com/w3c/2009/uxd-1-0-base#". The concepts of this vocabulary can then be referenced with CURIEs (compact URIs) of the form ux:{resource name}.

Additional namespaces are defined for groups of UXD context characteristics; see linked documents below.

UXD Context Characteristics

Context base concepts

The following are base classes that support the modeling of the context characteristics in which man-machine interaction takes place.

The user, the IT product, the environment

The user experience context is thought to be composed of 3 components: the user, the IT product, the environment. The IT product is further broken down into the platform (hard and software), and the application. The characteristics of each of these are defined in separate documents:

Usability and User experience quality aspects

To express the quality of the user interface of an IT product, we define the concept Usability quality.

Below, we also provide list of usability subcharacteristics. This list is mostly based on ISO/IEC 25010, a part of the SQuaRE series of standards on Systems and software Quality Requirements and Evaluation. ISO/IEC 25010 defines two separate models of quality characteristics: one for Quality in Use (which is similar to most's people's understanding of user experience quality), and another with intrinsic product quality characteristics. Quality in Use is not only determined by intrinsic product quality features, but also by characteristics of the users, tasks and social environment, the quality of the software, hardware and operating environment. However, the distinction between these two models is rather artificial when dealing with usability. The standard itself notices that: "Usability can either be specified or measured as a product quality characteristic in terms of its subcharacteristics, or specified or measured directly by measures that are a subset of quality in use." (See §4.2.4, note 2.) Below we list the most use quality characteristics from both view points.

User Experience / Usability Quality in Use

Usability can be measured and specified by the achieved user experiences quality in a real setting. User Experience quality is a subset of the Quality in use as defined in ISO/IEC 25010. User Experience (UX) characteristics that are related to usability include (based on ISO/IEC 25010):

Usability product quality attributes

Product characteristics that contribute to usability include (based on ISO/IEC 25010):

UXD Guidelines

A UXD guideline is a construct that expresses the correlation between one or more IT product characteristics, and their effect on achievable user experience quality. The guideline can also define the specific contexts in which this correlation can be expected. This context can be defined with inclusion and/or exclusion criteria.

Guideline

A typical guideline element contains 4 sub elements: title, description, what, when. These can be defined as follows:

	<div about="[myguideline1]" typeof="ux:Guideline">
		<p property="ux:title"> 
			... 
		</p>
		<p property="ux:description"> 
			... 
		</p>
		<p about="[myguideline1]" rel="ux:what">
			<a rel="ux:condition" ... />
			<a rel="ux:increases" ... />
			... 
		</p>
		<p about="[myguideline1]" rel="ux:when">
			<a rel="ux:inclusionCriterion" ... />
			... 
		</p>
	</div>

What property

The "what" property of a guideline expresses the core of the guideline. It identidies one or more product characteristics (i.e. application features) that, when present, will contribute to a better/worse user experience quality.

The What property is to be used as follows:

	<div about="[myguideline1]" typeof="ux:Guideline">
		<p about="[myguideline1]" rel="ux:what">
			Using <span property="ux:condition">clear screen texts</span>  
			leads to better<a rel="ux:increases" href="ux:UserExperienceQuality">user experience</a>. 
		</p>
	</div>

When property

The "when" property of a guideline expresses the context in which the guideline is valid. A guideline element can have multiple "when" properties, each expressing an alternative context in which the guideline is valid.

The When property is to be used as follows:

	<div about="[myguideline1]" typeof="ux:Guideline">
		This guideline applies in these conditions:
		<ul>
			<li about="[myguideline1]" rel="ux:when" >
				<a rel="ux:inclusionCriterion" href="ux-p:Laptop">Laptops</a> 
				(confidence <a rel="ux:confidence" href="[ux:ConfidenceVeryStrong]">***</a>) 
			</li>
			<li about="[myguideline1]" rel="ux:when" >
				<a rel="ux:inclusionCriterion" href="[ux-p:Tablet]">Tablets</a> 
				<a rel="ux:exclusionCriterion" href="[ux-a:Homepage]">home pages</a> 
				(confidence <a rel="ux:confidence" href="[ux:ConfidenceStrong]">**</a>) 
			</li>
		</ul>
	</div>