Ergonomics of human-system interaction—Usability methods supporting human-centred design
Some standard content:
ICS13.180
National Standard of the People's Republic of China
GB/T21051--2007/IS0/TR16982:2002 Ergonomics of human-system interaction-Usability methods supportinghuman-centred design
(ISO/TR16982:2002.IDT）
2007-08-23 Issued
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
Digital anti-counterfeiting
2007-12-01 Implementation
GB/T21051—2007/ISO/TR16982:2002 Foreword
Normative references
Terms and definitions
Appropriate deployment of usability methods
Usability methods
Usability in general Selection of usability methods
Appendix A (Informative Appendix) Recommended template for determining appropriate usability methods for specific projects Appendix B (Informative Appendix)
Appendix C (Informative Appendix)
References
Scenario application examples
Other methods and techniques
GB/T21051--2007/IS0/TR16982:2002 This standard is equivalent to ISO/TR16982:2002 "Human-system interaction ergonomics support usability methods for human-centered design" (English version), and is drafted based on the translation of ISO/TR16982:2002. Appendix A, Appendix B, and Appendix C of this standard are informative appendices. This standard is proposed by the China National Institute of Standardization. This standard is under the jurisdiction of the National Technical Committee for Ergonomics Standardization. Drafting units of this standard: China National Institute of Standardization, Lenovo Group, Institute of Psychology, Chinese Academy of Sciences, Dalian Maritime University, Beijing IL User Interface Design Co., Ltd., Air Force Aviation Medicine Research Institute, Tsinghua University. The main drafters of this standard are: Ran Linghua, Yang Wanli, Liu Taijie, Chen Baihong, Zhang Xin, Fu Xiaolan, Liu Zhengjie, Yuan Xiaowei, Guo Xiaochao, Li Zhizhong, Wang.
This standard is published for the first time.
GB/T21051—2007/IS0/TR16982:2002 Introduction
As a basic element in computer-based system development, "human-centered design" is increasingly valued. GB/T18978.11—2004 and GB/T18976—2003 provide "usability guidelines" and "human-centered interactive system design process". GB/T18976-2003 provides general guidelines for "human-centered" product design (hardware and software) and four main situations, but does not explain specific methods. This standard is intended to help project managers (with the support of ergonomics experts) make informed decisions when selecting usability methods: to support human-centered design as described in GB/T 18976-2003, but not to make project managers ergonomics experts.
This standard reviews existing usability methods, which can be used alone for design and evaluation or in combination. Each method is given its advantages and disadvantages and other factors related to its selection and use, including the impact of the project stage in the life cycle on the selection of usability methods.
Since the suitability of each usability method depends on the design activities being carried out, the usability method should be combined with the design process. GB/T 8566 provides a basic framework for evaluating the suitability of these methods. Appendix A provides a template for professionals, and Appendix B gives an application example of this template. Appendix C describes other methods and techniques in detail.
1 Scope
GB/T21051-2007/IS0/TR16982:2002 Ergonomics of human-system interaction
Usability methods to support human-centered
design
This standard presents human-centered usability methods that can be used for design and evaluation, and elaborates on the advantages, disadvantages and other factors related to the application of each usability method. This standard clarifies the influence of the life cycle stage and the characteristics of individual projects on the selection of usability methods, and provides examples of the application of usability methods in specific scenarios.
Since the main users of this standard are project managers, this standard only discusses technical ergonomic issues in the necessary depth so that managers can understand their relevance and importance in the design process as a whole. As a supplement to this standard, GB/T18978 gives a more comprehensive explanation of these issues. The main users of GB/T18978 are system developers, specification setters and system buyers. Nevertheless, all parties involved in the development of human-centered systems, including the end users of the systems, should benefit from the guidance in this standard. The guidance in this standard can be tailored to specific design situations by using a list of questions that characterizes the context in which the delivered product will be used. The selection of appropriate usability methods should also take into account the corresponding life cycle processes. This standard only describes methods that are widely used by usability experts and project managers. This standard does not specify the details of how to implement or execute the usability methods described. Note: Most methods require the involvement of ergonomics experts. People who lack the appropriate skills and knowledge may not be suitable for using these methods. 2 Normative references
The following documents have clauses that become clauses of this standard through reference in this standard. For dated references, all subsequent amendments (excluding errata) or revisions to these documents do not apply to this standard, however, parties to agreements based on this standard are encouraged to investigate whether the latest versions of these documents can be used. For undated references, the latest versions of these documents apply to this standard. GB/T8566 Information technology software life cycle process (GB/T8566-2001, idt ISO/IEC12207:1995) GB/T18905 (all parts) Software engineering product evaluation (ISO/IEC14598, IDT) GB/T18976-2003 Human-centered interactive system design process (ISO13407:1999, IDT) GB/T18978 (all parts) Ergonomic requirements for office use with visual display terminals (VDTs) (ISO9241, IDT) 3 Terms and definitions
The following terms and definitions apply to this standard. 3.1
Prototype prototype
A representation of the whole or part of a product or system that can be used for evaluation, although its representation is limited in some aspects. [GB/T18976-2003]
User user
An individual who interacts with the system.
［GB/T18978.10-2004]
GB/T21051—2007/IS0/TR16982:20023.3
usability
The degree to which a product can be used by a specific user for a specific purpose in a specific context of use, using effectiveness, efficiency and satisfaction as indicators.
[GB/T18978.11—2004]
usability methodusabilitymethod
Methods that support human-centered design with the goal of improving the usability of a product or system. 4 Appropriate deployment of usability methods
4.1 Overview
Usability methods help ensure that the developed system meets the usability goals of the human-centered design process (see GB/T18976—2003 for details).
The benefits of adopting a human-centered design approach include increased user satisfaction, improved productivity and work quality, reduced technical support and training costs, and improved user health and comfort. The usability methods described in this standard can support the achievement of these goals. When choosing an appropriate usability method, basic knowledge of usability methods is essential, including an understanding of the main differences between various methods and the basic principles of method application. Usability methods provide a way for deployed or to-be-deployed systems to increase the chances of achieving the above goals. 4.2 Basic principles proposed in GB/T18976-2003 GB/T18976--2003 confirms the following four basic principles: a) Based on the assessment of human capabilities and task requirements, functions are appropriately allocated between users and systems; b) Active user participation is required to enhance new systems and their acceptability; The system is designed based on the feedback information from users when using the early designed system c
d) The collaboration of multidisciplinary design teams, each of which actively participates and shares its knowledge and professional skills. Applying these principles can identify four important human-centered design activities, which should integrate usability requirements into the product development process, and these activities are carried out in succession until the established usability goals are achieved. Human-centered design activities include: understanding and clarifying the use context. This information can be collected through a variety of methods, and this standard is intended to help users make appropriate choices among these methods;
clarify user and organizational requirements;
generate designs and prototypes;
implement user evaluation.
4.3 Methods and their application
4.3.1 Methods and methodologies
The usability methods described in this standard are independent, that is, they can be selected and applied according to different self-concepts (for example, user needs analysis, requirements establishment, design and specification, and evaluation). Most of the methods can be used simultaneously or sequentially within the larger framework of human-centered design methodology. Such methodologies are not covered in this standard. Methodologies can come from specific selections of several methods in the same design process, or from methodologies commonly used or described in the ergonomics literature. Examples of such methodologies include behavioral and task analysis methodologies that combine interviews, user observations, questionnaires, and even experiments, and walkthrough and parallel design methodologies that combine various evaluation methods, expert and non-expert evaluations, and creative methods. Published methodological literature can be found in the references. 4.3.2 Design and evaluation perspectives
In general, the usability methods described in this chapter can be used for both design and evaluation. The specific choice (or selection) of usability methods depends on the design stage in which they are located, which is described in detail in Chapter 6. The main difference between design and evaluation in the use of usability methods lies in the different focuses:2
GB/T21051—2007/ISO/TR16982:2002--Design focus Confirm the user's knowledge, capabilities and limitations relative to the product or system design tasks. Particular attention is paid to ways that enable system and product designers to better understand user tasks and task vocabulary, user physiological capabilities, and other information. This information can be used to guide the design of systems or products to optimize their usability. This design focus often leads to the discovery of unexpected ways in which users view the operation or use of products or systems. These focuses may include comparisons of competing designs to determine which design is more useful. One is focused on evaluating a design in terms of performance or preferences of the user, using some measurement and data collection tools (e.g., questionnaires, error logging, and time stamping), in a specific aspect (e.g., interface features, recommendations, and standards), or against a model (e.g., user models, expected task completion times, and expected usage patterns). Knowing the differences in these measurement points, different usability methods can be applied to diagnose problems or facilitate design and redesign.
In the first case, usability methods are often called data collection techniques. Although they can also be used for evaluation, they are usually used in the project stage where jobs, tasks, and users are described and modeled with varying degrees of precision. In the second case, usability methods are often called evaluation methods, although they can also be used for design. The method can focus on the real system or prototype being evaluated, or even on an existing situation that has not yet been introduced into a computer system (e.g., when designing a new application software). In summary, all usability methods described in this chapter are human-centered methods that have a better grasp of usage situations and contexts. Therefore, they can be used to evaluate whether human-centered goals have been achieved (conduct evaluations) or to provide requirements, constraints, or suggestions for systems (models, scenarios, prototypes, or entire systems) that will be selected for evaluation in the future and are being designed. 4.3.3 Use of multiple methods
Chapter 5 describes various usability methods separately, but in actual applications, multiple methods can be used simultaneously. For example, interviews and observations can be used simultaneously. Moreover, different methods can be used to address different issues in the project life cycle. Using multiple methods can avoid being limited to a previously selected method. In order to achieve usability goals, the more methods are used, the better the results will be.
Multiple usability methods can be used in combination (for example, inspections and user testing, creative methods and formal methods, critical incident analysis and expert evaluation, questionnaires and interviews), and using multiple methods can increase the coverage of the results. Examples of situations where multiple usability methods are used are shown in Appendix B. 4.4 Direct user participation as a key factor
In the human-centered design process, active user participation is one of the key principles. Many of the usability methods described in this standard provide ways to obtain active user participation. In addition, there are many usability methods that do not require direct user participation because they can obtain information about user problems from other sources. These methods should be used as a supplement to methods that require active user participation. 4.5 Available methods
The most commonly used usability methods are presented in this standard. The various methods are shown in Table 1. Variants of these methods are referred to by other names. Some of the more well-known variant names (in books or on the Internet) are listed in the references. Usability methods can be divided into two major categories (see Table 1, column 2): methods with direct user participation (Y = yes); and methods without direct user participation (N = no), which are used when it is impossible to collect usable data through communication with users, or when these methods can provide supplementary data and information.
Brief description of the methods introduced in Table 1
Method name
User observation
Performance-related measurements
Are users directly involved?
Brief description of method
Accurately and systematically collect information about user behavior and performance in the context of specific tasks during user activities
Collect quantifiable performance measurement information to understand the impact of usability problems3
GB/T21051—2007/ISO/TR16982:2002Method name
Critical incident analysis
Thinking aloud
Collaborative design and evaluation
Creative methods
Document-based methods
Model-based methods
Expert evaluation
Automated evaluation
Are users directly involved?
4.6 Selection of Usability Methods (UM)
4 .6.1 Factors affecting the selection of methods
Factors affecting the selection of methods include:
a) life cycle stage;
b) user characteristics;
c) characteristics of the tasks to be performed;
d) the product or system itself:
Constraints affecting the project:
Table 1 (continued)
Brief description of methods
Systematically collect specific events (positive or negative) Use a pre-prepared questionnaire to collect users' views on the user interface Indirect evaluation methods are similar to questionnaires, but have greater flexibility and face-to-face interaction with interviewees Users constantly express their thoughts, beliefs, expectations, doubts, and discoveries while using the system being tested
Methods in which different types of participants (users, product developers, ergonomics experts, etc.) collaborate to evaluate or design the system
Methods inspired by new product and system characteristics, usually from interactions between team members. In the context of human-centered approaches, the team members are often user usability experts. Analyze existing documentation to make professional judgments about the system. Use an abstract model that represents the product being evaluated to predict user performance. Evaluation based on the ergonomics knowledge, professional skills, and practical experience of the usability expert focuses on usability criteria or uses algorithms from an ergonomic knowledge base system to diagnose product deficiencies relative to predetermined criteria.
f) The level of ergonomics expertise possessed by the development or evaluation team. 4.6.2 Appropriateness of the method
Based on the identified problem, the usability methods are evaluated based on the following five levels: Recommended (++):
Appropriate (+10);
Neutral (table cell is empty):
Not recommended (-1);
Not appropriate (NA).
There are a variety of alternative usability methods that can be used to collect the required information, some of which can be excluded because they cannot be used in a specific context. For example, when there are no current users, it is impossible to interview the users, so interviews are not appropriate (NA); on the other hand, if there are current users, but they are not fully representative of the characteristics of potential users, then interviews are appropriate (+10), but analytical methods are also recommended. Considering that poor design can lead to errors or low satisfaction, it is advisable to determine whether to use multiple methods in combination and the degree of sophistication of the methods required.
The above levels are based on typical usage scenarios and should be evaluated according to the specific project context. 4
5 Usability methods
5.1 Methods with direct user participation
5.1.1 Overview
GB/T21051—2007/IS0/TR16982:2002 This type of method is used in situations where user information can be collected directly or when users can be contacted. 5.1.2 User observation
This method is used to observe the activities of users when performing specific tasks in a real life environment or laboratory, and accurately and systematically collect user behavior and performance information. This observation is structured and based on predefined user behavior types. Most observation methods are based on detailed records of user behavior and subsequent data analysis. The advantages and disadvantages of this method are as follows:
This method can be applied in the context of a "real environment"; 1. Real activities are recorded.
Disadvantages (limitations)
Data analysis is time-consuming;
Proper interpretation of data requires professional knowledge; It is impossible to directly gain insight into the user's psychological process. The following are examples of the type of information that can be recorded and described quantitatively and qualitatively: The various behaviors that achieve the task objectives: Interactions with the computer, including physical activities, with other tools or with other people;
The number of attempts to complete the task;
Reasons for success or failure.
5.1.3 Performance-related measures
Performance-related measures are also called task-related measures. Commonly used quantifiable performance measurement information related to effectiveness and efficiency includes: time to complete tasks;
number of tasks that can be completed within the scheduled time; number of errors;
time to recover from errors;
-time required to find and interpret information in the user guide; number of commands executed;
number of system features that can be remembered;
frequency of use of support materials (documentation, help system, etc.); number of times user tasks are abandoned;
-number of times the topic is deviated;
length of idle time (need to distinguish delays caused by the system, user thinking time, and delays caused by external factors): number of important incidents
Performance-related measurements are often used for the entire system or local systems. The advantages and disadvantages of this method are as follows:
-collect quantifiable data;
results are easy to compare.
GB/T21051--2007/ISO/TR16982:2002 Disadvantages (Limitations)
May not reveal the cause of the problem:
A working version of the system or product is required. For other methods, see Appendix C.
5.1.4 Critical Incident Analysis
Critical incident analysis involves systematically collecting outstanding events in user performance. These events are recorded in the form of short reports that describe the facts related to the events. Data can be collected through user interviews and objective observations of interactive behaviors, and then these events are grouped and classified.
Performance-related measurements focus on current tasks and existing situations, while critical incident analysis studies major positive or negative events that may have occurred in the past or over a period of time. The advantages and disadvantages of this method are as follows:
Collect the causes of the problem;
Focus on events that are high in user requirements;
Record real activities.
Disadvantages (Limitations)
It may take a long time to complete:
Incomplete incident records affect the effectiveness of the analysis. 5.1.5 Questionnaires
At some point during development, it is helpful to use questionnaire items to collect user information. Questionnaire items can be either open-ended statements or list-based or closed-ended items and scales: the former have the advantage that people can give detailed answers, but there is a risk when only statements that are difficult to interpret and have ambiguous meanings are collected. Therefore, closed-ended questionnaire item forms are often preferred. Standardized questionnaires can also be used for systematic comparisons, for example, between design features or between competing designs. The type of data collected by questionnaires includes user quantitative information, suggestions, opinions, and ratings on systems, features, user assistance, preferences, ease of use, etc. Qualitative methods are usually indirect because they do not study user interactions, but rather users' views on user interfaces. Consistency checks on questionnaires are also necessary. For example, the same question item can be expressed in different question forms. Therefore, closed-ended questions are often preferred.
The advantages and disadvantages of this method are as follows:
- Reveal subjective preferences;
Easy to manage:
Quick to implement.
Disadvantages (limitations)
Using self-assessment to evaluate performance will lack reliability; Questionnaire items and answers are prone to bias. 5.1.6 Interviews
Interviews are similar to questionnaires, but because there is face-to-face interaction with the interviewee, they are more flexible. Interviews include a variety of different forms from highly structured to completely free-style. Interviewing users one by one requires more work time than processing a questionnaire.
However, the advantage of interviews is that they are more flexible, that is, when users are unclear about the questions, the interviewer can explain complex questions to users in more depth or ask questions in other forms. For answers that require further elaboration from users, or answers that present new insights that were not foreseen when the interview was designed, the interviewer can also ask follow-up questions. The advantages and disadvantages of this method are as follows:
Can quickly collect the overall situation of user opinions; flexible, and can investigate the reactions of each user. Disadvantages (Limitations)
Detailed analysis takes time;
Questions and answers are prone to bias:
- Correct interpretation of data requires professional knowledge. 5.1.7 Thinking aloud
GB/T21051—2007/1SO/TR16982:2002 Thinking aloud refers to the user's continuous verbal expression of his or her thoughts, beliefs, expectations, doubts, and discoveries during the use of the system. The rules of thinking aloud provide valuable information for understanding the user's motivation to perform certain behaviors, which is an important supplement to the objective data of user behavior obtained through observation, performance measurement, data recording or video. Users must be prompted to think aloud before starting, and the prompt must be repeated during this period. The method of verbal expression can be either simultaneous (for example, the user expresses his or her views while operating the system) or retrospective (the user expresses his or her views after completing the task and can choose to watch or not watch the video recording of the behavior). Experimenters generally prefer simultaneous verbalization because it avoids the possibility of users selectively processing or rationalizing their memories afterwards. The advantages and disadvantages of this method are as follows:
\—~Quick to implement;
The information collected can provide insight into the user's psychological processes; Flexible, each user's response can be investigated. Disadvantages (Limitations)
May be uncomfortable for some users; Detailed analysis takes time;
—Task performance data cannot be collected when using this method. See Appendix C for more details.
5.1.8 Collaborative design and evaluation
Collaborative methods involve different types of participants (users, product developers, ergonomics experts, etc.) working together when evaluating or designing a system.
Because use cases and/or user tasks may be difficult for designers and developers to understand, or users may have difficulty expressing their true requirements or needs during the development process, collaborative methods emphasize the importance of users playing an active role in design and evaluation.
In collaborative methods, the participation of users and developers is equally important. Collaborative methods focus on organizational issues and user work practices and use development tools that users are familiar with, for example, using prototypes instead of formal models. Collaborative methods focus on both quality and work efficiency. Future work situations can be demonstrated through simulations in real environments, for example, using role-playing methods. The advantages and disadvantages of this method are as follows:
Quick implementation:
Can be used in the early stages of a project;
Promote communication and learning between users, usability experts, designers, and developers. Disadvantages (Limitations)
May expose conflicts between the parties involved; - Task performance data cannot be collected when using this method. GB/T21051--2007/ISO/TR16982:20025.1.9 Creative methods
This type of method aims to obtain inspiration about new product and system features through interaction between team members. In the context of human-centered methods, the members of the team are often users. Creative methods are applicable to many fields, and by changing perspectives and considering options, a series of innovative products and (or) problem-solving ideas can be generated.
This type of method is not unique to ergonomics, but can be used in the context of human (user-centered) design methods. This type of method is more effective when users are involved, but it can also be used without users. This type of method is particularly suitable for the conceptual stage of the design process and can be used in the early stages of the project. This type of method helps to create and define the functions and interfaces of new products. The advantages and disadvantages of this approach are as follows:
Requires a variety of skills, but these skills are easier to acquire than other more specific ergonomic methods, especially in the early stages of a project.
Disadvantages (Limitations)
Detailed analysis is time-consuming:
- Can be biased.
5.2 Methods without direct user involvement
5.2.1 Overview
These methods can be used when there is an established body of knowledge, when direct data collection is not possible due to lack of contact with users, or when evaluation is being conducted in the earliest stages of design. Specifications for new products or systems can be based on or compared to the features or qualities required in "ergonomic interfaces". 5.2.2 Document-based methods
When using document-based methods (also called document-based analysis), the usability expert uses existing checklists or other documents in addition to personal judgment. The expert should have enough experience to use these documents in a way that is appropriate to the context of use and to effectively conduct the design or evaluation.
These documents are based on recognized rules or empirically verified examples and can be obtained from a variety of sources (e.g., scientific literature, standards, and style guides). bZxz.net
The advantages and disadvantages of this approach are as follows:
Expert knowledge is not always necessary, but it can improve the effect; it promotes communication and consistency between users, developers, and usability experts; it can be based on the latest knowledge.
Disadvantages (Limitations)
It may not cover all aspects of user interaction with the system; it takes a lot of time to be thorough.
Typical documents include:
Style guides, which can come from the software provider or be defined (customized) by the company using the product, and may require the help of ergonomics experts.
Manuals, which are guides of advice, are usually broader in scope than style guides and are generally based on the latest ergonomics knowledge. Standards, which can be corporate, national, or international standards, may contain recommendations that may become increasingly important as they become more accepted. For example, the ISO9241-13 to ISO9241-17 series of standards. Evaluation table, providing a list of attributes for a suitable ergonomic interface (as complete as possible). Each attribute is evaluated by adding a label within a certain range of values. These attributes may come from recognized ergonomic rules (usually organized into dimensions, 8
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