The following report is a report which i had to complete for my university physical ergonomics project, in which we had to outline and justify the steps we would take as designers in designing an ATM taking into consideration ergonomics and anthropemetric guidelines
Project Summary
In this report I will look into the ergonomic guidelines and design steps required to provide input into the: interface design, machine sitting and dimensions of an ATM. I will also provide design recommendations for the choice of a hand or eye recognition device, taking into account the different sectors of the concentric rings model (Girling and Birnbaum 1988).
Task considerations:
This stage requires me to understand the task at hand and how it will be performed. For me to provide input into the design of the user interface, I would use different Task analysis methods to help me break down the tasks and identify errors that might occur. First I would use HTA to help me in understanding the tasks involved in existing ATM’s starting with the goal and then sequence of tasks, also understanding what skills and decisions are needed from the users. Operational sequence diagram would be used to present the interaction and sequence of the tasks and finally I would use Link analysis to enable me to understand how each task is related in the system.
I would construct the diagrams by observing users using other ATM’s and conducting user surveys.
The output at this stage would be a HTA, Operational sequence and link analysis diagrams. With a short report detailing the list of tasks that would take place and their sequence, identified type of errors, type of feedback if available and decision required by the users.
User requirements considerations
The universal design method (Dix, A and Finlay, J, 2004,p.366) states that designers should not exclude anyone through the design choices they make,with that in mind, I must ensure that users needs are understood to establish what is required of the system. Considerations would include understanding user characteristics, their computing experience and their expectations of the system. User requirements include security, dispensing cash quickly and ease of use, others would be gathered using: focus groups, workshops, interviews, questionnaires and the aid of system mock ups. Ideally users would be involved throughout the design process but this can be costly.
I would also look into user persona’s, looking into more details of user requirements for 1) wheelchair users, 2) novice 3) elderly 3) left handed people, 4) stakeholders, attempting to meet their requirements, thereby “imposing the most sever constraints” (Pheasant, S and Haslegrave, C, (2006) p.27) on the design of the ATM.
I would also need to ensure the system is cognitively compatible, making its behaviour appear natural to the user. (Potter, D, Matthews, M, Ali, M (1997).
The output at this stage would be a user requirements document detailing system and functional requirements, with activity diagrams, ensuring they are included at the design and development stages.
Target population considerations
This stage requires me to identify the target audience who are intended to use the system. Since ATM’s are generally accessible by anyone with a bankcard, even customers of other building societies, the user population will be very large. So I need a realistic representative sample of that population, focusing on the limiting users, helping give me confidence in my data and to give as true a representation as possible of the intended users. I would first start by looking at the details of the current customers of the bank, through surveys and interviews to help me in identifying the characteristics of the users: such as age, gender and maybe their attitude towards technology. Then look at their computer experience (novice or experts) also analyse their possible usage levels based on their account activity. And to help me with my anthropometric data and ergonomic design, I would need to look at people dimensions (focusing on the 5th%ile, 50th%ile and 95th%ile.) in that geographical location. Also focusing on the percentage of disabled users, the elderly, dyslexic people etc.Data of right handed and left handed users is also important in the design to ensure buttons are designed to accommodate both groups. The anthropometric data would be gathered through user testing, or using existing data such as from Body space (Pheasant, S and Haslegrave, M.(2006)).
The output of this stage would be a documentation detailing the findings from the research, with percentages of types of users (such as elderly, disabled, novice) but also recommendations of the dimensions of the systems to meet the limiting users. With diagrams to better represent those dimensions.
Environmental considerations:
At this stage I need to consider the physical environment in which the ATM will be used. Where the system is to be used (on a main road?). Also will the users be standing or sitting? And if there’ll be enough space to perform the task which may affect how users use the system and their acceptance of it, as it may create security issues. Using user discussions and questioning ATM users on their current issues with ATMs, I can understand the type of issues that exit.
Since the ATM will be placed outside, there are several environmental aspects to consider such as:
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Lighting: different lighting level of the screen and the area should be tested to ensure the best lighting level is chosen, enabling people to see the screen clearly. Also using glare-reducing films would be ideal. Rain can be an issue, so an ATM positioned deep into the wall and at an angel could reduce this problem.
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Noise: With the ATM being outside, any sound feedback to the user may not be heard and users may not be aware that they made an error. This is particularly an issue for users with visual impairment as they may depend on the sound to recognise errors.
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Position of ATM & time: it’s critical for ATM to be positioned in a safe location to reduce crime. Also since ATM’s are available 24 hours, it would be better to have an indoor ATM for better security. Which will encourage users to use the machine.
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Privacy screens as used on computers would be ideal to stop people seeing account data.
Using prototypes and mock-ups I would be able to better understand these issues and identify others.
The outcome of this would be a report of the list of issues discovered and ways to reduce them or eliminate them from the design, and recommendations of location, system aspects and features.
Application of guidelines and anthropometry
This stage aims to clarify the ergonomics guidelines and needs, with research of anthropometric data to ensure the final design accommodates the physical difference of the users. I would collect anthropometric dimensions from as many people as possible in the area, or using dimensions in Bodyspace (Pheasant, S and Haslegrave, M.(2006). Taking into account the dimensions and needs of the limiting users such as the elderly & wheelchair users. I would need to collect the stature, shoulder breadth, vertical reach for standing and seated users and elbow height. And since users will be interacting with a screen, I would need to calculate the comfortable viewing distance, with the preferred/acceptable display zones, also the buttons and screen need to be at a comfortable distance for any one standing or seated. Hand dimensions need to be investigated to help in the design of the buttons to operate the ATM. Measurements of palm length and index finger length, looking at both left and right-handed users. Finger dimensions would be particularly important for a palm reader if it is to be incorporated into the design. For an iris reader to be developed, accurate eye scan would be required from the users when they approach the system. This means users would need to be at a specific distance from the screen and would need to be looking at the reader. This poses a number of issues, as users are of different heights and the eye scanner would need to be able to reach both standing and seated users. Adjustable features would be a possible design feature. These design outcomes would be collected through discussions, questionnaires and a fitting trial to test how users interact with different dimensions of the system.
Other design features to consider would be the layout and design of buttons and how they are presented to the user. Different colours on the screen to be tested, ensuring there is a contrast between the text and background. Text font and size is also important, ensuring all users can see and read outcomes on the screen, with visual cues and clear error messages to aid the user through their task.
The outcome of this stage would be a report detailing the findings, dimensions and anthropometric results and recommendations for the design. Sketches and images would also be included.
Development of ergonomic design limitations
Using existing results from the user data and existing research in the area, I would conduct further user testing on those limiting users to help me in identifying the specific design limitations imposed by them. This would enable me to break down the task to identify key areas which would need to be addressed before development, specifically what design features and dimensions they would require.
Previous data from the user population stage would be further analysed and refined, giving me a better understanding of the limiting user segment. Further information would be collected from published British standards papers to ensure the dimensions meet those guidelines. I would then be able to design mock up/prototypes of the ATM to test it on those users.
Although it maybe impossible to design a system that meets everyone’s full requirements, the system should still allow all users to use it as effectively and efficiently as possible, without excluding anyone.
The outcome of this stage would be a list of design considerations to meet the limiting user needs, with specific design dimensions of the ATM, such as height, width, sitting reach and measurements to provide a clear visual area. Diagrams would also be used which would aid in the physical deign stage.
Testing
Once the design features and ergonomic design criteria has been agreed upon, a prototype would then be created and fully tested on the target users. Users opinions and issues experiences would be collected through questionnaires, discussions or observations. A walkthrough would be ideal at this stage, as I would be able to walk through the task steps with the user.
The output at this stage would be a test results document outlining any issues and their severity, which then be analysed further, to allow for design improvements and recommendations.
Iterative evaluation
Following the user testing outcomes, changes would be implemented to the design where possible, to ensure it is optimised for the user. Further testing would then occur to revaluate those changes. It’s vital that the changes are applied before development, as it would be very costly to make changes then. This stage may take place a number of times until all the issues are resolved.
As specified in Bodyspace (Pheasant, S and Haslegrave, M.(2006), p.5), the criteria to ensure the product matches it’s user and intended task is to ensure that it is:
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Functionally efficient
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Easy to use
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Comfortable for the user
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Health and safety issues resolved
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And provides good quality to its users.
So it’s important that throughout the design stages for these steps to be met and finalised before it’s used by the users to ensure a successful and usable system is in place.
Design recommendations
For the ATM to be usable by its intended users, it needs to be easy to use with no training required. It needs to provide the users with clear feedback and error messages explaining to the user what has gone wrong and what to do next. Users need to be given sufficient time before their access times out, as currently ATM’s have a short time count whilst the user is interacting with the system.
Also, users need to be given more power in undoing tasks, as currently this is not available.
Better visual cues are recommended, reducing the amount of information, which needs to be read on screen. Eg. Flashing light where card is when it is ready to collect.
It’s important to ensure the buttons are large enough for people with bigger hands, and easy to press, therefore not requiring much force.
Ideally the machine should have a security screen so users from the side or distance cannot see information on screen.
Also, the location of the ATM is critical, because if it is located on a very busy road with no personal space area, users may be put off due to security reasons.
Currently some machines have ear phone features for the visually impaired, this is very good to allow the users to use the machine. Ability to change the volume is needed, since background noise can be very loud. Also, the use of headphone means users information cannot be heard by others and therefore safer.
Regarding the palm and iris reader, although they would be beneficial in double checking the person’s identify before allowing them access, the biometric may change over time , such as injury to the eye or scarring to the fingers. This would affect the reading. Also, previous cases show that identify theft may occur and people may still attempt to access user’s information, so there is a security aspect.
In the case of the iris reading, it is reading very sensitive information when scanning the eyes, therefore positioning of the camera or the target area to scan is critical to the reading. This could be difficult to meet with people of different physical features (very tall, very short) or users in wheelchairs. Also the distance from the scanner, the background objects and lighting could affect the eye scanning.
I would recommend a palm reader, as it would be easier to use by the majority of users, but it’s position and height would be critical to it’s usage. As it would need to be of a height which meets both the standing and seated. It needs to allow people to place their hand at a comfortable angle, otherwise it may strain the muscle if this is done frequently.
One issue to consider would be for the scanner to remain clean as this could affect the reading, which means users would not be able to withdraw cash.
Finally as a note for future design projects, for the designers not to separate the machine and interface design process, to allow them to relate the screen experience with the physical experience of the whole machine.
References:
Books
Pheasant, S and Haslegrave, M. ( 2006) . Body Space: Third edition.
Faulkner,X. (2000). Usability Engineering
Bridger,R.S (2003). Introduction to ergonomics. 2nd edition.
Norman,D.A (2002). The design of everyday things.
Diaper,D. (1989). Task analysis for human-computer interaction.
Raskin,J.(2000). The Humane Interface.
Dix, A. Finlay, J. Abowd, G. Beale, R. (2004). Human-Computer Interaction.
Websites:
Sweeney,H.A. Applying ergonomic principles in the workplace. Retrieved November 27, 2007 from http://www.alexandertechnique.com/ergonomics.htm
Science Blog, (1997) retrieved November 20, 2007 from http://www.scienceblog.com/community/older/1997/B/199701526.html
Anderson, R. (1999) Perspectives - Automatic Teller Machines. Retriever November 27, 2007 from http://axion.physics.ubc.ca/atm.html
Articles:
Rogers, W.A., Cabrera, E.F., Walker, N., Gilbert, D.K., and Fisk, A.D. (1996). 38. 156-166.A Survey of Automatic Teller Machine Usage Across the Adult Life Span
Long J, Timmer, P (2001/3). (64). Design problems for cognitive ergonomics research: what we learn from atm-like micro-worlds