Accessibility Principles Jim Carter USERLab University of Saskatchewan

Accessibility Principles Jim Carter USERLab University of Saskatchewan © Jim A Carter Jr 2012

Principle “"a law or rule that has to be, l or usually is to be followed, l or can be desirably followed, l or is an inevitable consequence of something, l such as the laws observed in nature l or the way that a system is constructed"” 1 l l Wikipedia. com CMPT 480/840 Accessibility Principles 2

General use of principles l Principles provide high level ergonomic guidance l l that act as goals to be worked towards rather than objectives that can be fully achieved l Principles can be used to help identify more specific requirements and recommendations l Principles can be applied to evaluation and design l of systems, products, services, facilities, built environments, etc. CMPT 480/840 Accessibility Principles 3

Organizing the Principles l can be based on the UARM CMPT 480/840 Accessibility Principles 4

User-Focused Principles l User-focused principles l emphasize the individual users who have accessibility needs l Suitability for the Widest Range of Users Conformity with User Expectations Suitability for Individualization Suitability for Engagement l l l CMPT 480/840 Accessibility Principles 5

Suitability for the Widest Range of Users l A system is suitable for the widest range of users l if it is acceptable and available to the users throughout a user population with the widest possible range of capabilities, taking account of their special abilities, variations in their capabilities, the diversity of their tasks, and their differing environmental, economic and social circumstances. l if it meets the needs of user populations with the widest range of characteristics, capabilities and tasks in differing environmental, economic, social, and cultural circumstances. l l l CMPT 480/840 NOTE 1 This principle advocates universal accessibility rather than targeting specific groups of users. NOTE 2 This principle recognizes that the goal of accessibility is to benefit as many people as possible. NOTE 3 This principle includes the needs of older persons and person with disabilities. Accessibility Principles 6

Measuring S. for the Widest Range l Effectiveness issues include: l l l Efficiency issues include: l l The range of various capabilities that are contained within the user population that is served by the interactive system The ratio of users contained within the user population served by the interactive system to the number of users in the entire population that might be served by the interactive system. Various measures of efficiency achieved by users with characteristics representing extreme ranges within the user population Satisfaction issues include: l Various measures of satisfaction reported by users with characteristics representing extreme ranges within the user population CMPT 480/840 Accessibility Principles 7

Conformity with User Expectations l A system conforms to user expectations l if it is predictable based on the contextual needs of the user and on commonly accepted conventions l if it is predictable based on the user's experience, the context of use and/or on commonly accepted conventions l l CMPT 480/840 NOTE 1 This principle is about meeting users' reasonable expectations. NOTE 2 This principle is especially important to persons with different levels of cognitive / learning skills and capabilities. Accessibility Principles 8

Measuring Conformity w User Expectations l Effectiveness issues include: l l l Efficiency issues include: l l Consistency of similar actions throughout the system Obviousness of system states that modify the effect of interaction components Naturalness of data structures and application layout Consistency of behavior and appearance across similar tasks Immediacy of feedback on user actions Consistency of time for the system to complete similar actions The frequency of the user being surprised by system responses to user actions. Satisfaction issues include: l The comfort and familiarity that the user experiences in interacting with the system CMPT 480/840 Accessibility Principles 9

Suitability for Individualization l A system conforms to suitability for individualization l if users can modify the operations, interactions, content, and components of the system to suit their individual capabilities and needs. l if users can modify its operations, interactions, content, and/or components to suit their individual characteristics, capabilities and tasks. l l CMPT 480/840 NOTE 1 This principle recognizes that a single solution is seldom optimal in meeting the needs of all users and contexts of use. NOTE 2 This principle can be met by providing users with a choice of alternative solutions. NOTE 3 This principle is important for making solutions more usable for individuals with different sensory, physical and cognitive characteristics and capabilities. NOTE 4 This principle advocates providing individualization capabilities rather than requiring users to use technical aids (e. g. Assistive Technologies). Accessibility Principles 10

Measuring S. for Individualization l Effectiveness issues include: l l Efficiency issues include: l l The individual items that are individualized The ability for the user to control / override any system-initiated individualizations The correspondence of the results of the individualization to the wants and needs of the user Improvements in system performance resulting from individualizations The use of system-initiated in situations where it is suitable and aids the user The ease of the user to initiate / control / override the individualization activities Satisfaction issues include: l l User attitudes regarding the system serving their unique needs Increase / decrease in levels of user frustration with how the system operates CMPT 480/840 Accessibility Principles 11

Suitability for Engagement l An interactive system is suitable for the engagement l when it motivates the user to choose to use it whenever it might be of assistance in performing the user's tasks. l NOTE: While this was not proposed to the Guide 71 meeting l l l The need for a similar principle was suggested to me by at least one delegate as a possible additional principle that might be suggested in the near future It is an existing ergonomic principle from ISO 14915 -1 CMPT 480/840 Accessibility Principles 12

Measuring Suitability for Engagement l Effectiveness issues include: l l Efficiency issues include: l l Users repeatedly choosing to use this interactive system from among a number of competing interactive systems. E. g. customers doing repeat business with an e-Commerce site. The ratio of cost of retaining users to the cost of attracting new users Satisfaction issues include: l Various measures of user experience CMPT 480/840 Accessibility Principles 13

Interaction-focused principles l emphasize the individual interactions (including the sharing of information content and functionality) l Perceivability Understandability Controllability Reachability l l l CMPT 480/840 Accessibility Principles 14

Perceivability l A system is perceivable l if users can successfully recognize the various content and functions it presents. l if users can sense the information and functionalities it presents. l l l CMPT 480/840 NOTE 1 This principle depends on the ability of users to perceive information through different senses (e. g. visual, auditory, tactile, olfactory). NOTE 2 This principle recognizes that making use of multiple senses can reinforce the perception. NOTE 3 This principle is important to ensure that individuals with different sensory, physical and cognitive characteristics and capabilities can perceive information and functionalities in a wide variety of contexts of use. Accessibility Principles 15

Measuring Perceivability l Effectiveness issues include: l l l Efficiency issues include: l l The recognition of content and controls needed to perform a given task The presentation of content and controls in a manner that can be perceived via multiple modalities The speed of recognition of content and controls needed to perform a given task Satisfaction issues include: l The satisfaction / frustration with being able to find the content / controls needed to perform a given task CMPT 480/840 Accessibility Principles 16

Understandability l A system is understandable l if the meaning and the functionality of the content and the operations of the system are obvious to the user. l if its information and functionalities are clear to the user. l l CMPT 480/840 NOTE 1 This principle is about correctly interpreting the meaning of what has been perceived. NOTE 2 This principle recognizes that it is important for a solution to minimize the need to learn and to remember. NOTE 3 This principle recognizes that where it is necessary to learn and to remember this should be as easy as possible. NOTE 4 This principle recognizes that people with different cognitive and language characteristics and capabilities will have different needs in understanding the information and functionalities of the solution. Accessibility Principles 17

Measuring Understandability l Effectiveness issues include: l l l Efficiency issues include: l l l The ability of a user to utilize the system without the need for obtaining help. The frequency of needing to obtain help The ability to comprehend and operate according to the current state of the interactive system The ability of the user to comprehend and make use of content presented by the system Time for the user to identify the interaction elements of the system to use for the next step in their interaction The frequency of making errors or slips due to misunderstandings Satisfaction issues include: l The users' level of confidence in being able to interact with and make use of the content. CMPT 480/840 Accessibility Principles 18

Controllability l A system is controllable l if the user is able to initiate and control the direction and pace of the interaction until the point at which the goal(s) has/have been met. l if the user is able to initiate and carry out interaction(s) towards accomplishing the task. l l l CMPT 480/840 NOTE 1 This principle depends on the ability of users to use different physical control mechanisms (e. g. touch, gesture, voice) to interact with the solution. NOTE 2 This principle recognizes that providing a choice of physical control mechanisms and/or combinations of physical control mechanisms can improve controllability. NOTE 3 This principle is important to ensure that people with differing sensory, physical and cognitive characteristics and capabilities can control functionalities in a wide variety of contexts of use. Accessibility Principles 19

Measuring Controllability l Effectiveness issues include: l The presence of controls that provide various types of controllability to users The ability of users to control all decisions made by the system l The ability of users to change/reverse decisions after they have been made l l Efficiency issues include: l l The average number of actions required by a user to execute a range of control actions Satisfaction issues include: l l Comfort with the ability to control the system (as long as the complexity of this ability does not become overwhelming) The feeling that the system is there to serve the users rather than the users being there to serve the system CMPT 480/840 Accessibility Principles 20

Reachability l A solution is reachable l if the user can physically access it to carry out the task. l l NOTE 1 This principle depends on the ability of users to approach the solution. This principle l l l CMPT 480/840 is being suggested to be added to the Guide 71 principles and is based onon "Size and Space for Ease of Use" from Design for all is only applicable to physical objects Accessibility Principles 21

Task-focused principles l emphasize the ability for interactions to achieve intended accomplishments l Suitability for the task /Usability Error avoidance Suitability for Learning l l CMPT 480/840 Accessibility Principles 22

Usability l A system is suitable for the task l l After much debate and without full unanimity l l if it supports the user in the completion of the task with effectiveness, efficiency, and satisfaction. the principle was renamed but retained the same wording A solution is usable l if it supports the user in the completion of the task with effectiveness, efficiency, and satisfaction. l New notes are to be created! CMPT 480/840 Accessibility Principles 23

Measuring Suitability for the Task l Effectiveness issues include: l l Efficiency issues include: l l Having all the information and controls available to complete the task Being assisted by the system in completing the task correctly Avoiding situations that might lead to errors and providing extra assistance in situations that cannot be avoided Avoiding excessive steps and distractions to be able to get the task accomplished as quickly and simply as possible Satisfaction issues include: l l Recognizing that the system can be applied to the task and trusting that it will get the task accomplished Feeling satisfied that steps are actually necessary and not a waste of your time CMPT 480/840 Accessibility Principles 24

Error Tolerance l An interactive system is error-tolerant l if despite evident errors in input, the intended result may be achieved with either no, or minimal, corrective action by the user l if despite predictable errors, the intended task can be achieved with either no, or minimal, corrective action by the user l l l CMPT 480/840 NOTE 1 This principle recognizes that it is important to minimize all possible errors and their impact. NOTE 2 This principle recognizes that the occurrence of errors can be particularly disturbing to some users, causing them to panic or respond in a manner that might lead to failure to complete the task. NOTE 3 This principle recognizes that some people with differing sensory, physical and cognitive characteristics and capabilities can experience higher than usual occurrences of errors. Accessibility Principles 25

Measuring Error Tolerance l Effectiveness issues include: l l Efficiency issues include: l l The breadth/type of errors that are tolerated, corrected, etc. (a positive) The types of errors that are not tolerated (a negative) The frequency of errors that cause the system to fail The cost of error tolerance measures vs. the costs produced by the occurrence of errors (this relates to the insurance value of providing error tolerance – it is not worthwhile to spend more to handle errors than the costs they create if they are not handled by providing error tolerance) Satisfaction issues include: l l The trust users will have in a system because they will know/believe that their actions will not cause the system to fail The freedom users will experience in trying different actions where they have confidence that they can recover from errors/slips CMPT 480/840 Accessibility Principles 26

Suitability for Learning l A system is suitable for learning l l if it provides support and guidance to the user when necessary before and during using the system After much debate and despite the importance of this principle to people with cognitive / learning disabilities l this principle was deleted on the grounds of being l l CMPT 480/840 being redundant with understandability and other principles being a special case of a task (even though suitability for the task was removed/renamed Accessibility Principles 27

Measuring Suitability for Learning l Effectiveness issues include: l l l Efficiency issues include: l l The ability of the user to correctly perform a task immediately after accessing some form of learning-related guidance The ability of the user to correctly perform a task without first accessing some form of learning-related guidance Minimization of the number of times the user accesses learning / relearning / help Minimization of the time spent learning / requesting help Decreases in the number of times / amount of time that the user access learning / relearning / help over an extended period of time Satisfaction issues include: l l The level of confidence users have with regards to their ability to use the system without the need of accessing learning-related guidance The level of mastery the users report having with regards to using the system CMPT 480/840 Accessibility Principles 28

Task-focused principles l Major changes were made to the task-focused set l l l The generic Suitability for the task was renamed Usability Error avoidance was retained Suitability for Learning was deleted l CMPT 480/840 as being a special case of suitability for the task and understandability Accessibility Principles 29

System-focused Principles l System-focused principles l emphasize technical issues which could impact upon achieving accessibility l Equitable use Interoperability Transportable without damage l l CMPT 480/840 Accessibility Principles 30

Equitable Use l A system provides equitable use l if it accomplishes the same tasks for all users: in an identical manner whenever possible; in an equivalent manner when not. [wording not changed] l l CMPT 480/840 NOTE 1 This principle encourages the adoption of strategies (where an identical manner can serve all users) that limit the need for using technical aids (e. g. Assistive Technologies). NOTE 2 This principle recognizes that there are circumstances (where an identical manner is not possible) that are appropriate for using technical aids (e. g. Assistive Technologies). NOTE 3 This principle recognizes that the need to do extra, unnecessary work can make a task too difficult for some people with differing physical skills and capabilities. NOTE 4 This principle is focused on minimizing any extra burdens of use on persons with differing sensory, physical and cognitive characteristics and capabilities. Accessibility Principles 31

Measuring Equitable Use l Effectiveness issues include: l l Efficiency issues include: l l The ratio of users contained within the user population that can use the interactive system without the need for Assistive Technology to the total number of users in the entire population that are served by the interactive system. Various ratios of efficiency achieved by users (with characteristics representing extreme ranges within the user population) who use the interactive system without the need for Assistive Technology to the efficiency achieved by users with the same characteristics who use Assistive Technology with the interactive system Satisfaction issues include: l The ratio of various satisfaction measures reported by a user (with characteristics representing extreme ranges within the user population) when using the interactive system without Assistive Technologies to those satisfaction measures reported when using Assistive Technologies CMPT 480/840 Accessibility Principles 32

Interoperability l A system provides robustness l l if it provides interfaces and functionalities to allow it to work with current and future assistive technologies. A solution provides interoperability l if it provides interfaces and functionalities to allow it to work with technical aids (e. g. Assistive Technologies). l CMPT 480/840 NOTE 1 This principle recognizes that while it is not feasible to make all solutions directly accessible to all people, the provision of interoperability can make it possible for persons with differing sensory, physical and cognitive characteristics and capabilities to use their technical aids (e. g. Assistive Technologies). to utilize the solution. Accessibility Principles 33

Transportable without Damage l A system / information content l l is transportable without damage if after it is transported it includes all the content and functionality that it contained before being transport. After a little debate, this principle was deleted as not being general enough to apply to all types of solutions l (systems, products, services, facilities, built environments) CMPT 480/840 Accessibility Principles 34

Is that all there is? ? ? l While what you looked at were principles that were intended to be important to accessibility, l there might be additional principles we should consider CMPT 480/840 Accessibility Principles 35