This part of GB/T 18978 defines usability and describes how to identify the information that must be considered when defining or evaluating the usability of a VDT (visual display terminal) based on the measurement of user performance and satisfaction. It gives guidance on how to clearly describe the context of use of a product (hardware, software or service) and the related usability measurements. This guide only gives general principles and techniques, but does not give requirements for the use of specific methods. The guidance given in this part can be used for procurement, design, development, evaluation and communication of usability information. This part contains guidance on how to define and evaluate the usability of a product. It is applicable to products intended for general use as well as products that have been acquired or are being developed within a specific organization. This part also describes how the measurement of user performance and satisfaction can be used to measure the impact of any part of a work system on the entire work system in use. This guide contains usability measurement procedures, but does not detail all the actions taken. The specification of detailed, user-based measurement methods is beyond the scope of this part, but further information can be found in Appendix B and references. This part applies to office work using VDTs. It also applies to other situations where users interact with products to achieve their goals. The recommendations provided in Parts 12 to 17 of GB/T18978 apply only to specific usage contexts. The guidelines in this part of GB/T18978 can be used in conjunction with Parts 12 to 17 of GB/T18978 to help identify the applicability of the recommendations. This part focuses on usability and does not comprehensively cover all the goals of ergonomic design covered by GB/T16251. However, usability design will certainly contribute to the achievement of ergonomic goals, such as reducing the adverse effects on human health, safety and performance that may occur during use. This part does not cover the system development process. The human-centered interactive system design process is described in GB/T18976-2003. GB/T 18978.11-2004 Ergonomic requirements for office work using visual display terminals (VDTs) Part 11: Usability Guide GB/T18978.11-2004 Standard download decompression password: www.bzxz.net
This part of GB/T18978 defines usability and explains how to identify the information that must be considered when defining or evaluating the usability of VDTs (visual display terminals) based on the measurement of user performance and satisfaction. It gives guidance on how to clearly describe the use context of the product (hardware, software or service) and the related usability measurements. This guide only gives general principles and techniques, and does not give requirements for the use of specific methods. The guidance given in this part can be used for procurement, design, development, evaluation and communication of usability information. This part contains guidance on how to define and evaluate product usability. It is applicable to products intended for general use as well as products that have been acquired or are being developed within a specific organization. This part also explains how measurements of user performance and satisfaction can be used to measure the impact of any part of a work system on the entire work system in use. This guide contains procedures for measuring usability, but does not detail all the actions taken. The specification of detailed, user-based measurement methods is beyond the scope of this standard, but further information can be found in Annex B and the references. This standard applies to office work using VDTs. It is also applicable to other situations where users interact with products to achieve their goals. The recommendations provided in parts 12 to 17 of GB/T 18978 are only applicable to specific usage contexts. The guidance in this part of GB/T 18978 can be used in conjunction with parts 12 to 17 of GB/T 18978 to help identify the applicability of various recommendations. This part is dedicated to usability and does not comprehensively cover all the goals of ergonomic design covered by GB/T 16251. However, usability design will certainly contribute to the achievement of ergonomic goals, such as reducing adverse effects on human health, safety and performance that may occur during use. This part does not cover the system development process. The human-centered interactive system design process is described in GB/T 18976-2003.
GB/T18978 "Ergonomic requirements for office work using visual display terminals (VDTs)" covers the ergonomic requirements for hardware and software involved in the use of visual display terminals, and is intended to be divided into the following 17 parts:
- Part 1: Overview;
- Part 2: Task requirements guide;
- Part 3: Visual display requirements;
- Part 4: Keyboard requirements;
- Part 5: Workbench layout and posture requirements;
- Part 6: Work environment guide;
- Part 7: Display requirements with reflection;
- Part 8: Display color requirements;
- Part 9: Requirements for non-keyboard input devices;
- Part 10: Dialogue principles;
- Part n: Usability guidelines;
- Part 12: Information display;
- Part 13: User guide;
- Part 14: Menu dialog;
- Part 15: Command dialog;
- Part 16: Direct operation dialog;
- Part 17: Form filling dialog.
This part is Part 11 of GB/T 18978.
This part is equivalent to ISO9241-11:1998 "Ergonomic requirements for office work using visual display terminals (VDTs) Part 11: Usability guidance" (English version).
This part is drafted based on the translation of ISO9241-11:1998.
The references in this part correspond to Appendix Ee of ISO9241-11:1998
Appendices A to D of this part are informative appendices.
This part is proposed by China National Institute of Standardization.
This part is under the jurisdiction of the National Technical Committee on Ergonomics Standardization.
The drafting units of this part: China National Institute of Standardization, Lenovo Group Co., Ltd., Dalian Maritime University, Institute of Software, Chinese Academy of Sciences, Institute of Psychology, Chinese Academy of Sciences, and the Fourth Institute of Air Force.
The main drafters of this part: Chen Yuanqiao, Yang Wanli, Liu Zhengjie, Chen Baihong, Dai Guozhong, Fu Xiaolan, Guo Xiaochao
The clauses in the following documents become the clauses of this part through reference in this part of GB/T 18978. For any dated referenced document, all subsequent amendments (excluding errata) or revisions are not applicable to this part. However, the parties to an agreement based on this part are encouraged to study whether the latest versions of these documents can be used. For any undated referenced document, the latest version applies to this part.
GB/T 16251-1996 Ergonomic principles for work system design (eqv ISO 6385:1981)

ICS 13.180
National Standard of the People's Republic of China
GB/T 18978.11—2004/ISO 9241-11: 1998 Ergonomic requirements for office work with visual displayterminals( VDTs)-Part 11: Guidance on usability(ISO 9241-11:1998,IDT)
Published on 2004-05-10
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China Administration of Standardization of the People's Republic of China
Implemented on 2004-12-01
GB/T 18978.11--2004/IS0 9241-11: 1998GB/T18978\Ergonomic requirements for office use with visual display terminals (VDTs)\Covering the ergonomic requirements for hardware and software involved in the use of visual display terminals, it is divided into the following 17 parts: Part 1 Overview
Part 2: Guide to business requirements:
Part 3: Visual display requirements:
Part 4: Keyboard requirements:
Part 5: Workstation layout and posture requirements; Part 6: Work environment guidelines:
Part 7: Workstation layout and posture requirements; Part 8: Work environment guidelines:
Part 9: Workstation layout and posture requirements; Part 10: Workstation layout and posture requirements; Part 11: Workstation layout and posture requirements; Part 12: Work environment guidelines:
Part 13: Workstation layout and posture requirements; Part 14: Work environment guidelines:
Part 15: Workstation layout and posture requirements; Part 16: Work environment guidelines:
Part 17: Workstation layout and posture requirements; Part 17: Work environment guidelines:
Part 18: Workstation layout and posture requirements; Part 18: Workstation layout and posture requirements; Part 1998GB/T18978\Ergonomic requirements for office use with visual display terminals (VDTs) Part 7: Requirements for displays with reflection;
Part 8: Color requirements for displays;
-· Part 9: Requirements for non-keyboard devices; Part 10: Dialog principles:
Part 11: Usability guidelines:
Part 12: Information display:
- Part 13: User guide:
Part 14: Menu dialog;
. Part 1· Command dialog:
- Part G· Direct manipulation dialog:
Part 17 Part; Fill in the form dialogue
This part is part 11 of GB/T 18978
This part is equivalent to IS) 924 [-[1: 1998 Ergonomic requirements for office work using visual display terminals (VDTs) Part 11: Usability Guide (English version)
This part is drafted based on the translation of IS09241-11, 1998. The references of this part correspond to Appendix E of IS09241-11.: 1998. Appendices A to D of this part are informative appendices. This part is proposed by China National Institute of Standardization. This part is submitted by the National Ergonomics Standardization Technical Committee. The drafting units of this part: China National Institute of Standardization, Lenovo Group Co., Ltd., Dalian Maritime University, Institute of Software, Chinese Academy of Sciences, Institute of Psychology, Chinese Academy of Sciences, Konghandi Institute, and the main drafters of this part: Chen Erqiao, Yang Wanli, Liu Zhengjie, Chen Baihong, Dai Guozhong, Fu Xiaolan, Guo Xiaochao. GB/T18978.1--2004/1S0 9241-11:1998 introduces the goal of designing and evaluating the usability of VTT (visual display terminal) is to use it to achieve the national standard and meet the needs in the context of use. This part of GB/T18978 explains the benefits of measuring usability in terms of user effectiveness and satisfaction. Usability can be measured by the following aspects: The degree to which the expected use goals are achieved: - the resources consumed to achieve the expected goals; - the degree to which users consider the use of the product acceptable. This part emphasizes: VLY usability depends on the context of use; the level of usability achieved depends on the specific environment in which the product is used. The context of use consists of the user, the service, the equipment (hardware, software and raw materials), and the physical and social environment, all of which affect the usability of a product in a work system. User performance and satisfaction measurements can be used to evaluate the entire work system. When a product is of interest, these measurements provide information about the usability of the product in the context of the specific convenience provided by the rest of the work system. The impact of changes in the rest of the work system (for example, user training or improved lighting conditions) can also be measured through user performance and satisfaction. The term "usability" is sometimes also used in a narrow sense to refer to the attributes of a product that are easy to use (see Appendix I). (Other parts of GB/I18978 provide requirements and recommendations related to the attributes of hardware, software and environment that can promote the usability of VDTs, as well as the ergonomic principles implied therein.
1 Scope
GB/T 18978.11—2004/IS0 9241-11: 199E Ergonomic requirements for office use with visual display terminals (VDTs) Part 1, Usability Guide This part of GB/T 18978 defines usability and explains how to identify the information that must be considered when defining or evaluating the usability of a VDT (visual display terminal) based on measurements of user performance and satisfaction. It gives guidance on how to clearly describe the context of use of a product (hardware, software or service) and related usability measurements. This guide only gives general principles and techniques, and does not give requirements for specific activities of use.
The guidance given in this part can be used to purchase, design, develop, evaluate and communicate scientific usability information. This part contains guidance on how to define and evaluate the usability of a product. It applies both to products intended for general use and to products that have been acquired or are being developed within a specific organization.
This part also describes how measurements of user performance and satisfaction can be used to measure the impact of any part of a work system on the entire work system in use.
This part The guidance contains procedures for measuring usability, but does not provide details of all actions to be taken. The specification of detailed, user-friendly methods of measuring angles is beyond the scope of this part, but further information can be found in Annex B and the references. This part of ISO 9001 applies to office work using VDTs. It also applies to other situations in which users interact with products to achieve their objectives. The recommendations provided in parts 12 to 17 of ISO 9001 apply only to specific contexts of use. The guidance in this part of ISO 9001 can be used in conjunction with parts 12 to 17 of ISO 9001 to help identify the applicability of various recommendations. This part of ISO 9001 focuses on usability and does not cover all the objectives of ergonomic design covered by ISO 9001. However, usability design will certainly contribute to the achievement of ergonomic objectives, such as reducing the adverse effects on human health, safety and performance that may occur during use.
This part of ISO 9001 does not cover the system development process. The human-centered interactive system design process is described in ISO 9001. 18576-2003.
2 Normative references
The following documents have become the terms of this part through reference to this part of GB/T 18978. For any referenced document with an H date, all subsequent amendments (excluding errata) or revisions are not applicable to this part. However, parties to an agreement based on this part are encouraged to investigate whether the latest versions of these documents can be used. For any undated referenced document, the latest version applies to this part.
GB/T 16251-1996 Ergonomic principles for the design of work systems (eqv ISO 6385:1981) 3 Terms and definitions
The following terms and definitions apply to the content of this part of GB/T 18978. 3.1
Usability
The degree to which a product can be used by a specific user for a specific purpose in a specific context of use, with effectiveness, efficiency and satisfaction as indicators.
For other methods and approaches to achieve usability, see Appendix D. YYKAONTKAca
GB/T18978.11---2004/IS0 9241-11:19983.2
Effectivenesseffectiveness
The accuracy and completeness with which users achieve specific goals. 3.3
Efficiencyefficiency
The consumption of resources corresponding to the accuracy and completeness with which users achieve their goals. 3.4
Satisfaction
No discomfort and a positive attitude towards the use of the product. 3.5
Conlext of use
Users, tasks, equipment (hardware, software, and raw materials), and the physical and social environment in which the product is used. 3.6
work system
Work system
In order to achieve a specific standard, the userThe system of devices, tasks, and physical and social environments. Note: Usability consists of those parts of the working system that are considered known when defining or measuring usability. 3.7
User
The individual who interacts with the product.
Objective
The desired outcome.
Task
The activities necessary to achieve the goal.
Goal 1: These activities may be physical or cognitive. Note 2 to entry: Job duties may determine goals and tasks. 3.10
Product
The part of the equipment (hardware, software, and other materials) whose usability is to be defined or evaluated. 3.11
Measurement measure (noun)
The value obtained by a measurement method and the process by which it is obtained: 4 Rationale and solution
Because usability concerns the degree to which users of a product can operate effectively, efficiently, and satisfactorily, it is an important consideration in product design. Product usability can be improved by incorporating known features and attributes that benefit users in a specific context of use. To determine the level of usability achieved, it is necessary to measure the performance and satisfaction of users in operating with the product. Usability measurement methods are particularly important given the complexity of the interactions between the use, goals, task characteristics, and the context of use. The level of usability of a product may vary significantly when used in different contexts. As part of product design and development, usability planning involves the systematic identification of usability requirements, including usability measurements and verifiable descriptions of the context of use. It provides design objectives that can be used as a basis for verifying design results. The benefits of the approach used in this part of GI3/T18978 include: GB/T 18978.11--2004/IS0 9241-11: 1998 When defining, designing or evaluating the usability of a product, the framework can be used to identify the aspects of usability and the components of the usage context to be considered:
User performance (effectiveness and efficiency) and satisfaction can be used to measure the degree to which the product is usable in a specific context; for products with different technical characteristics used in the same context, measures of user performance and satisfaction can provide a basis for comparing the relative usability of products;
The planned usability of the product can be defined, documented and verified (for example, as part of a quality plan). 5 Definition and measurement of product usability
5.1 Framework for defining usability
5.1.1 Purpose
This framework describes the components of usability and their relationships to each other. 5.1.2 Usability Components wwW.bzxz.Net
To define or measure usability, it is necessary to identify the goals and decompose the components of effectiveness, efficiency, satisfaction, and context of use into subcomponents with measurable and verifiable attributes. The components and their interrelationships are shown in Figure 1. User
Use
5.1.3 Required Information
Expected Outcomes
Usability: The degree to which the goals are achieved in terms of effectiveness, efficiency, and satisfaction Effectiveness
Expected Results
Figure 1 Usability Framework
When defining or measuring usability, the following information is required:
Satisfaction
Usability Measurements
Description of the components of the context of use (including users, tasks, devices, and environment). This can be a description of the existing context or a detailed description of the intended context. The relevant aspects of the context and the level of detail described will depend on the scope of the problem being addressed. The context description should be detailed enough so that those contextual aspects that have a significant impact on usability can be reproduced; target values ​​or actual values ​​of effectiveness, efficiency and satisfaction in the expected context. 5.2 Objective description
The objectives of product use should be described. Objectives can be broken down into sub-objectives, and sub-objectives define the components of the overall objective and the criteria for meeting the overall objective. For example, a clerk using telephone sales may have the objective of "maintaining customer orders", which can be broken down into the following sub-objectives:
"Accurately record all customer orders"; "Provide quick response information to customer order inquiries". The level of the overall objective set depends on the scope of the work system considered to provide the context of use. In the above example, the work system considered consists of clerks who accept telephone orders. 5.3 Use recording
5.3. 1 User Description
The relevant characteristics of the user need to be described. This may include knowledge, skills, experience, education and training, physiological characteristics, and motor and sensory abilities. It is necessary to define the characteristics of different types of users (e.g. users with different experience levels or users in different roles). 5.3.2 Task Description
Tasks are activities performed to achieve a goal: characteristics of tasks that may affect usability should be described, such as the frequency and duration of tasks:
If the context description is to be used as the basis for designing or evaluating the details of interaction with the product, then a detailed description of activities and processes should be included. This may include an anchor description of the distribution of activities and steps between people and technical resources. Tasks are not completely captured in terms of the functions or features provided by the product or system. Any description of the activities and steps involved in performing a task should be related to the objective to be achieved.
For the purpose of assessing usability, a representative group of key tasks can be selected to represent the important aspects of the overall task. Note that task analysis can be used to identify the user's tasks and the tasks (progressive tasks). (See references for information). 5.3.3 Equipment Description
The relevant characteristics of the equipment need to be described. The description of the hardware, software, and raw materials associated with the VIYT can be described in terms of a set of products (or system components), one or more of which may be the focus of a usability specification or evaluation, or in terms of a set of attributes or performance characteristics of the hardware, software, and other raw materials. 5.3.4 Environment Description
The characteristics of the physical and social environment need to be described. Aspects to be described include the attributes of the broad technical environment (e.g., local area network), the physical environment (e.g., workplace, furniture), the ambient environment (temperature, humidity), and the social and cultural environment (work practices, organizational structure, and attitudes).
5.3.5 Examples
Appendix A gives examples of how the components of the context of use can be described in terms of usability-related characteristics. 5.4 Usability Measurements
5.4.1 Choice of Measurements
It is usually necessary to provide at least one measure for each of effectiveness, efficiency, and satisfaction. Because the relative importance of the various components of usability depends on the context of use and the usability goals being described, there are no general guidelines for how to select measures or combine measures. The choice of measures and the level of detail of each measure will depend on the common objectives of the parties involved in the measurement, and the relative importance of each measure relative to the objective should be considered. For example, for infrequent usage, measures of learning and relearning may be considered more important. If objective measures of effectiveness and efficiency are not possible, then subjective observations based on user perceptions may provide an indication of effectiveness and efficiency.
5.4.2 Effectiveness
Effectiveness measures may relate user objectives or sub-objectives to the accuracy and completeness of achieving those objectives. For example, if the intended goal is to accurately reproduce a two-page document in a specified format, then accuracy may be defined or measured by the number of writing errors and the number of deviations from the specified format, and completeness may be defined or measured by the number of words in the converted document divided by the number of words in the source document.
5.4.3 Efficiency
Efficiency measurement can relate the level of effectiveness achieved to the consumption of resources, which can include: psychological or physical effort, time, raw materials or financial costs. For example, human efficiency can be defined by effectiveness divided by human psychological or physical effort; time efficiency can be defined by effectiveness divided by time consumption; economic efficiency can be defined by effectiveness divided by cost. If the expected goal is to print a copy of a report, then efficiency can be defined or measured by the number of usable copies of the printed report divided by the resources consumed on the task (for example: labor time, processing costs and raw material consumption): 5.4.4 Satisfaction
Satisfaction can measure the degree of user discomfort and attitude towards the use of the product. GB/T 18978.11--2004/IS> 9241-t1:1998Satisfaction may be defined and measured by subjective ratings on a scale (e.g., discomfort experienced, liking for the product, satisfaction with the use of the product, or acceptability of the workload when performing different tasks), or by the degree to which specific usability criteria (e.g., efficiency and ease of learning) are achieved. Other measures of satisfaction may include the number of positive and negative comments recorded during use. Additional confidence may be obtained from long-term measurements (e.g., absenteeism, observations of cognitive or physical overload or underload of users), or from reports of health problems or the frequency with which users request a job change.
5.4.5 Further examples
Further examples of measures used for usability evaluation are included in Appendix 13 and the Appendix. 5.5 Interpretation of measurement results
Caution should be exercised in generalizing any measure of usability to other contexts where the types of users, tasks, or environments are significantly different. If usability is obtained using short-term measurements, then the results may not take into account infrequent events that can have a significant impact on usability, such as system errors that occur during a shutdown.
For general-purpose products, it is often necessary to define or measure usability in a variety of typical contexts (subsets of possible contexts and tasks that can be performed). Usability may vary in these contexts. 6 Usability specification and evaluation during design
6.1 Specification of the context in which the product is intended to be used
Before developing specific usability requirements, information about the characteristics, goals and tasks of users and the environment in which the tasks are performed can provide important information for the specification of the overall requirements for the product.
6.2 Specification of product usability requirements
In order to derive products that are specifically suited to their needs, organizations can use the information in ISO 14001-1 as a framework to define the usability requirements that the product should meet, and the usability requirements for acceptability testing based on this framework, before developing the specification of product usability requirements. The specific contexts in which usability should be measured should be identified, measures of effectiveness, efficiency and satisfaction should be selected, and acceptability criteria based on these measures should be established (an example is given in Annex C). 6.3 Product Development
The definition and framework of usability can help the product development team reach a common understanding of the concept of usability and help the product development team grasp the scale of product usability-related issues.
Developers can use the guidance of GB/T 18978.11 to define product usability goals (see Appendix (C). At different stages of the development process, developers measure the achieved usability against these goals. Based on this information, developers can make objective decisions on whether the design needs to be changed to enhance usability and how to make appropriate trade-offs between usability and other requirements. 6.4 Specification or evaluation of product attributes
Guidelines on usage context can be used to identify users, tasks, and environments in order to make accurate judgments on whether specific product attributes are needed.
6. 5 Usability measurement
GR/T 18978.11 provides information to support usability measurement. For example, descriptions of user characteristics can help select users for evaluation. Identification of user characteristics can help select appropriate usability test or review tasks: if the environment must be simulated to ensure the validity of the measurement results, the characteristics of the environment (in which the product is likely to be used) need to be described. GB/T 18978.11 also provides a basis for the development of usability measurements. Product developers can develop appropriate methods to measure efficiency, effectiveness and/or satisfaction (see Appendix B). 6.6 Introducing usability into the quality plan
The activities listed in 6.1 to 6.5 can be included as part of the quality plan to provide a basis for defining, documenting and verifying usability. Figure 2 summarizes the relationship between these activities and the results documents and other output forms. These can be included in any quality plan (for example: according to GB/T 18978.11-2004/IS0 9241-11:1998GB/T19000.3),
Identify usage scenarios
Select usability standards and measurements
Evaluate usability
Measure new design
Figure 2 Usability activities and related documents
6.7 Comparative evaluation of products
Document, output
Use to realize
Usability specifications
To meet the criteria
GB/T The guidance in IEC 6078.11 can be used to assist in making a choice between available products. Once usability requirements have been defined in terms of the intended objectives, the context of use, and the effectiveness, efficiency, and satisfaction measures to be used, the guidance can be used to define test conditions and evaluation criteria that are representative of the important aspects of the overall context of use. 6, 8 Use in conjunction with other national standards Other parts of IEC 6078 (e.g., the forthcoming IEC 6078.11/ISO)922114) contain recommendations applicable to specific contexts of use. The guidance in IEC 6078.11 can be used to provide a framework for identifying the objectives and use cases that are relevant to the design decisions to be made. Annex D contains more information on the relationship to other parts of IEC 6078 and other national standards. 7 Defining and measuring work systems in use 7.1 Relationship to usability Any part of a work system can be the subject of design or evaluation if the goal is to improve the entire work system. Effectiveness, efficiency and satisfaction measures may be used to assess any part of a work system, for example, appropriate consideration may be given to the provision of user training, changes in lighting conditions or the reorganization of tasks. In each case, while the element that is the subject of design or assessment is considered to be affected by the potential change, other elements of the work system are assumed to be constant. When a product is the focus, these measures provide information about the usability of the product in the specific context of use provided by the rest of the work system. 7.2 Application examples
7.2.1 Design of a complete work system When designing a complete work system, usability may be optimized by changing components of the product's context of use (e.g. operating system version, lighting or amount of user training). In this case, effectiveness, efficiency and satisfaction measures may be used to define or assess, respectively, the effect of a new version of the operating system, different types of lighting or different amounts of user training. 7.2.2 Diagnostic evaluation
If the work system is judged to be unsatisfactory, a systematic analysis of the role played by the different components of the context of use should be undertaken. In order to determine the main cause of the problem, it is necessary to consider both the direct effects of all components of the use context and the interactions between them. This process can be used to identify the components of the use context that need to be changed to improve the entire work system. Diagnostic activities related to the use context usually need to determine whether the problem originates from this product or from other parts of the work system. Appendix A
(Informative annex)
GB/T 18978.11—2004/IS0 9241-11:1998 Examples of how to define use contexts
Table A.1 (based on [27 and [22]) gives an example of how to define use contexts based on usability-related attributes. The use context of a product used in a specific context can be defined by its title. The product specification can be described in terms of relevant characteristics or summarized by a specific example. When defining a specific product instance that can be customized, it is advisable to specify the adaptations made to the default characteristics of the product. Verifiable and repeatable usability descriptions require that usability measurements in a specific context are repeatable. Unless the usability evaluation is to be conducted under actual usage conditions, it will be necessary to decide which actual or expected usage context attributes will be described in the context defined for the evaluation. Therefore, when defining or evaluating usability, it is important that the chosen context represents the important aspects of the actual or expected usage context. Particular attention should be paid to those attributes that are considered to have a significant impact on the usability of the product. Not all of the attributes listed in the examples in Table A.1 are appropriate for any particular situation, and other attributes may be used. Table A.1Examples of using contextual attributes
User type
Primary user
Secondary and indirect users
Skills and knowledge
Product skills/knowledge
System skills/knowledge
Task experience
Organizational experience
Training level
Skills in using input devices
Language proficiency
Individual attributes
Physical abilities
Physical limitations and disabilities
Intellectual abilities
Organizational environment
Working hours
Group work
Work function
Work routines
Task breakdown
Task name
Task frequency
Task duration
Event frequency
Service flexibility
Physical and psychological needs
Task dependence
Service output
Risk caused by errors
Safety requirements
Technical environment
Raw materials involved
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Basic description
Product logo
Product summary
Main application scope
Main functions
Software and hardware
Material services
Other items
Physical environment
Workplace conditions
Atmospheric conditions
Auditory environment
Thermal environment
Visual environment
Environmental instability
GB/T 18978.112004/1IS0 9241-11:1998 Use
Interruptions
Management structure
Communication structure
Attitudes and culture
Policies regarding computer use
Organizational goals
Industrial relations
Job planning
Job flexibility
Performance monitoring
Effectiveness feedback
Work pace
Autonomy
·Judgment
Table A1 (continued)
Workplace design
Air conditioning and furniture
Posture
Workplace safety
Health hazards
Protective equipment
B. 1 Overall usability
Appendix B
(Informative Appendix)
Examples of usability measurements
GB/T18978.11—2004/IS09241-11:1998 Usability effectiveness, efficiency, and satisfaction measures can be defined for overall objectives (e.g., writing a letter) or for specific objectives (e.g., performing a search and replace). Selecting usability measures for the most important user objectives may mean ignoring many features, but this is probably the most practical approach. Table B.1 gives examples of appropriate measurements. Table B.1 Examples of usability measures
Usability goals
Overall usability
Effectiveness measures
Percentage of goals achieved;
Percentage of users who successfully completed a task;
Average positive rate of completed tasks
B.2 Measures of desired product characteristics
Efficiency measures
Time to complete a task:
Amount of tasks completed per unit of time;
Money cost of performing the task
Desirability
Satisfaction rating scale:
Degree of use determined by discretion:
Frequency of desired use
For specific product characteristics that are desired to contribute to usability, additional measures may be required. Examples of some characteristics and additional specialized measures are given in Table 2. In addition, the measures given in Table B.1 may also be used for the usability objectives given in Table B.2, where appropriate.
Table B.2 Examples of measures of desired product characteristics Usability criteria
Satisfy trained users
Satisfy untrained users
Satisfy needs for infrequent or intermittent use
Minimize support requirements
Learnability
Error tolerance
Readability
Effectiveness measures
Number of significant tasks performed:
Percentage of relevant functions used
Tasks completed successfully on first attempt|| tt||redistribution rate
percentage of tasks successfully completed after a specified period of non-use
number of references to documentation:
number of requests for support;
number of visits to online help
number of functions learned:
percentage of users achieving learning goals
percentage of errors corrected or reported by the system;
number of tolerance for user errors
efficiency measures
relative effectiveness compared to that of experienced users =Efficiency
Time spent on first attempt;
Relative efficiency of first attempt
Time spent on relearning the function,
Number of errors in repeated products
Time to exert effectiveness;
Learning time to reach the standard
Learning time to reach the standard;
Real efficiency of learning
Time to correct errors
Read a specific number of words correctly under normal circumstances ( Percentage of textual content
Time spent on language
In these examples, resources related to a particular level of effectiveness can be measured as follows:-YYKAONIIKAca
Satisfaction scale
Rating of satisfaction with important features
Percentage of perceived use
Percentage of repeat use
Rating of satisfaction with support tools
Learning ease rating scale
Rating scale for error handling
Rating scale for visual discomfort2. Measures of desired product characteristics
Efficiency measure
Time to complete a task:
Amount of work completed per unit of time;
Money cost of performing the task
Satisfaction
Satisfaction rating scale:
Dependent use:
Desired frequency
Additional measures may be required for specific product characteristics that are expected to contribute to usability. Examples of certain characteristics and additional specialized measures are given in Table 2. In addition, where appropriate, the measures given in Table B.1 may also be used for the usability criteria given in Table B.2.
Table B.2 Examples of measures of desired product characteristics Usability criteria
Satisfy trained users
Satisfy untrained users
Satisfy needs for infrequent or intermittent use
Minimize support requirements
Learnability
Error tolerance
Readability
Effectiveness measures
Number of significant tasks performed:
Percentage of relevant functions used
Tasks completed successfully on first attempt|| tt||redistribution rate
percentage of tasks successfully completed after a specified period of non-use
number of references to documentation:
number of requests for support;
number of visits to online help
number of functions learned:
percentage of users achieving learning goals
percentage of errors corrected or reported by the system;
number of tolerance for user errors
efficiency measures
relative effectiveness compared to that of experienced users =Efficiency
Time spent on first attempt;
Relative efficiency of first attempt
Time spent on relearning the function,
Number of errors in repeated products
Time to exert effectiveness;
Learning time to reach the standard
Learning time to reach the standard;
Real efficiency of learning
Time to correct errors
Read a specific number of words correctly under normal circumstances ( Percentage of textual content
Time spent on language
In these examples, resources related to a particular level of effectiveness can be measured as follows:-YYKAONIIKAca
Satisfaction scale
Rating of satisfaction with important features
Percentage of perceived use
Percentage of repeat use
Rating of satisfaction with support tools
Learning ease rating scale
Rating scale for error handling
Rating scale for visual discomfort2. Measures of desired product characteristics
Efficiency measure
Time to complete a task:
Amount of work completed per unit of time;
Money cost of performing the task
Satisfaction
Satisfaction rating scale:
Dependent use:
Desired frequency
Additional measures may be required for specific product characteristics that are expected to contribute to usability. Examples of certain characteristics and additional specialized measures are given in Table 2. In addition, where appropriate, the measures given in Table B.1 may also be used for the usability criteria given in Table B.2.
Table B.2 Examples of measures of desired product characteristics Usability criteria
Satisfy trained users
Satisfy untrained users
Satisfy needs for infrequent or intermittent use
Minimize support requirements
Learnability
Error tolerance
Readability
Effectiveness measures
Number of significant tasks performed:
Percentage of relevant functions used
Tasks completed successfully on first attempt|| tt||redistribution rate
percentage of tasks successfully completed after a specified period of non-use
number of references to documentation:
number of requests for support;
number of visits to online help
number of functions learned:
percentage of users achieving learning goals
percentage of errors corrected or reported by the system;
number of tolerance for user errors
efficiency measures
relative effectiveness compared to that of experienced users =Efficiency
Time spent on first attempt;
Relative efficiency of first attempt
Time spent on relearning the function,
Number of errors in repeated products
Time to exert effectiveness;
Learning time to reach the standard
Learning time to reach the standard;
Real efficiency of learning
Time to correct errors
Read a specific number of words correctly under normal circumstances ( Percentage of textual content
Time spent on language
In these examples, resources related to a particular level of effectiveness can be measured as follows:-YYKAONIIKAca
Satisfaction scale
Rating of satisfaction with important features
Percentage of perceived use
Percentage of repeat use
Rating of satisfaction with support tools
Learning ease rating scale
Rating scale for error handling
Rating scale for visual discomfort
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