(From Scott Willmott)
Virtual and augmented realities are both non-command user interfaces and thus make it more difficult to evaluate and assess their levels of usability. The standard usability tests implemented for command user interfaces are difficult to implement as many of their principals either do not apply or are out of context.
Johnson’s (1998) claim that summative evaluations are inappropriate for the evaluation of desktop VR because he says that “it is hard to find valid statistical measures that support summative evaluation of desktop VR”
At present there are various usability tests which can be adapted and incorporated into evaluating the usability of these systems, I believe the most effective and useful for these technologies would be the heuristics adopted to test the usability of video games. Although there are no specific pre-defined heuristics for evaluating the usability of games, after carrying out research it is obvious that most of them are based around and upon the following three areas, which were defined by Clanton (1998):
- The Game Interface
- The Game Play
- The Game Mechanics
The Game Interface would include the visual representation of the system, therefore would be responsible for the consideration of such things as the screen layout, What is contained within the screen, how feedback is relayed back to the user, how items are displayed within the screen, how the user is able to view the items on screen and asses how much the user is required to know or learn in order to use the system effectively.
The Game Mechanics would be concerned with how the system works, how the user is required to interact with the system and what is the outcome of the user’s interactions with it. It is also responsible for the production of feedback to the user with regards to actions they perform or outcomes of the system.
The Game Play would be, in this case concerned with how the user feels when interacting with the system, the user should always feel in control of the system and confident in what they are doing or what they are trying to achieve, as well as feeling confident of being able to cope with any errors should they occur.
For a full set of example heuristics covering these 3 main topic areas see the following white paper links:
http://melissafederoff.com/heuristics_usability_games.html#heuristics_literature
www.behavioristics.com/downloads/usingheuristics.pdf
Virtual and augmented realities are both non-command user interfaces and thus make it more difficult to evaluate and assess their levels of usability. The standard usability tests implemented for command user interfaces are difficult to implement as many of their principals either do not apply or are out of context.
Johnson’s (1998) claim that summative evaluations are inappropriate for the evaluation of desktop VR because he says that “it is hard to find valid statistical measures that support summative evaluation of desktop VR”
At present there are various usability tests which can be adapted and incorporated into evaluating the usability of these systems, I believe the most effective and useful for these technologies would be the heuristics adopted to test the usability of video games. Although there are no specific pre-defined heuristics for evaluating the usability of games, after carrying out research it is obvious that most of them are based around and upon the following three areas, which were defined by Clanton (1998):
- The Game Interface
- The Game Play
- The Game Mechanics
The Game Interface would include the visual representation of the system, therefore would be responsible for the consideration of such things as the screen layout, What is contained within the screen, how feedback is relayed back to the user, how items are displayed within the screen, how the user is able to view the items on screen and asses how much the user is required to know or learn in order to use the system effectively.
The Game Mechanics would be concerned with how the system works, how the user is required to interact with the system and what is the outcome of the user’s interactions with it. It is also responsible for the production of feedback to the user with regards to actions they perform or outcomes of the system.
The Game Play would be, in this case concerned with how the user feels when interacting with the system, the user should always feel in control of the system and confident in what they are doing or what they are trying to achieve, as well as feeling confident of being able to cope with any errors should they occur.
For a full set of example heuristics covering these 3 main topic areas see the following white paper links:
http://melissafederoff.com/heuristics_usability_games.html#heuristics_literature
www.behavioristics.com/downloads/usingheuristics.pdf
www.ipsi.fraunhofer.de/ambiente/pergames2006/final/PG_Roecker_Usability.pdf
Another method of measuring usability would be to take an ethnographic approach, and observe the users as much as possible using the proposed technlogies, and include these findings wihtin the design stage, in order to highlight exactly what they want and how they want it to be achieved.
There are various techniques that can be adopted to achieve this, some of which are:
- Shadowing – Watch target users, gather information on their requirements and how they achieve certain tasks
- Diary Studies – Ask users to keep diaries commenting on their usage and good and bad points of the system
- Activity Studies – Ask users to achieve tasks as they would normally and highlight any issues or views
Other Usability tests that should be considered would be a pervasive usability test, as it directly relates to the technologies concerned with pervasive computing, thus Virtual and Augmented Reality.
Pervasive Usability
Pervasive usability is the evaluating of a design’s usability at each stage during the design process. Pervasive Usability is different from other usability evaluations in that it is not only conducted at the start of a projects lifecycle but throughout the whole process.
There are 3 main steps within pervasive usability testing which are:
- Analyze
- Conceptualize
- Final Design, Hosting and Maintenance
A full definition of what is carried out at each one of the above stages can be found at the following link:
http://www.sitepoint.com/article/planning-uncertain-future
Usability Findings
Due to the lack of usability testing carried out on the next generation interfaces and technologies there are only very limited result sets to analyse and comment on. Although, below are some usability issues highlighted by Jakob Nielsen within his paper on non-command user interfaces
Feedback – The production of feedback to users is one of the predefined usability heuristics, achieving this in some more next generation interfaces may be much more difficult. This may relate to how a person interacts with the system for example with virtual reality, the movement of a user may not be recognised by the system thus feedback would be required informing the user of this. Also if a users movement or gesture is required for system interaction then there will be delay in providing feedback to the user as the system can not achieve this until the complete movement and/or gesture has been completed.
Navigation was another area for concern highlighted within this resource. A study conducted by two interface specialist’s evaluated virtual reality, using a head mounted display and a glove to move around. The findings were that the movement of the user by walking was very accurate where as the movement initiated by a hand gesture was less accurate and on many occasions caused confusion when the gesture was not intentional.
Full study of these usability issues can be found at:
http://www.useit.com/papers/noncommand.html
References
-Melissa Federoff (2002), melissa federoff thesis [online] available from http://melissafederoff.com/heuristics_usability_games.html#heuristics_literature [25th April 2008]
-Desurvire, Caplan (n.d), Toth Using Heuristics to Ealuate The Playability of Games [online] available from http://www.behavioristics.com/downloads/usingheuristics.pdf [25th April 2008]
- Carsten Röcker, Maral Haar (n.d.) Exploring the Usability of Video Game Heuristics for Pervasive Game Development in Smart Home Environments [online] available from http://www.ipsi.fraunhofer.de/ambiente/pergames2006/final/PG_Roecker_Usability.pdf
[28th April 2008]
-Suneet Kheterpal Pervasive Usability [online] available from http://www.sitepoint.com/article/planning-uncertain-future [28th April 2008]
- Jakob Nielsen NonCommand User Interface [online] available from http://www.useit.com/papers/noncommand.html [26th April 2008]
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