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3.13 Human Factors 3.13-

3.13-1 Human factors for video display terminals standards 3.13-

3.13 Human Factors. Human factors (ergonomics) is the science of determining proper relations between computer systems and the user. Ease of use, comfort, health, and safety are primary concerns (e.g., how a keyboard should be laid out). An ergonomically-designed product implies that the device blends smoothly with the user's body or actions. For computing systems, these standards provide guidelines and requirements for the design of computer hardware, software user interfaces, and computing environments.

3.13.1 Human factors for computer hardware. Human factors requirements for computer hardware concern the user's physical interface through input devices and displays and how well it serves the needs of the user. Health and safety concerns are also addressed.

3.13.1.1 Human factors for video display terminals. (This BSA appears in both part 3, User Interface, and part 13, Human Factors.) This base service area addresses the human factors requirements for all types of video displays, and includes safety concerns.

3.13.1.1.1 Standards. Table 3.13-1 presents human factors standards for video display terminals.

DOD Instruction (DODI) 8120 mandates use of the DOD HCI Style Guide.

AIIM is the Association for Image and Information Management.
ECMA is the European Computer Manufacturers' Association.
HFS is the Human Factors Society.
NSC is the National Safety Council.

ISO 9241-1 presents an overview of the content and usage of the multipart ISO 9241 standard. A revised version of ISO 9241-1 is currently at the Committee Draft (CD) level and will soon be released for Draft International Standard (DIS) ballot. ISO 9241-2 presents an overview of factors that should be considered when designing tasks to be performed in a specific computing environment.

3.13.1.1.2 Alternative specifications. There are no alternative specifications available.

3.13.1.1.3 Standards deficiencies. The performance-based test described in ISO 9241-3 adequately discriminates between a display that meets the physical requirements of the standard and one that does not. However, timing scores may be badly affected by the effects of testing practice. Changes to the test method and metrics are under consideration. ISO 9241-3 does not adequately address flat panel displays. ISO 13406 is intended to remedy this situation.

3.13.1.1.4 Portability caveats. No portability problems are known with the above specifications.

3.13.1.1.5 Related standards. The following standards are related to human factors standards for video display terminals:

3.13.1.1.6 Recommendations. Procurements that require hardware components to be addressed by ergonomic standards can require conformance with standards for computer displays. Display characteristics include brightness and contrast, character legibility, image stability, glare, and the use of color.

Note, however, that ISO human factors/ergonomics standards are either normative or informative. An informative standard contains no mandatory requirements. A normative standard contains one or more requirements that must be met in order to achieve conformance with the standard.

ISO 9241-1 presents an overview of the content and usage of the multipart ISO 9241 standard. A revised version of ISO 9241-1 is currently at the Committee Draft (CD) level and will soon be released for Draft International Standard (DIS) ballot. ISO 9241-2 presents an overview of factors that should be considered when designing tasks to be performed in a specific computing environment.

Parts 1 and 2 of the ISO 9241 standard are informative. Part 3 of the ISO 9241 standard is normative; parts 2-9 are expected to be normative on completion. Conformance requirements for each normative part are embedded within that part. Conformance with the overall ISO 9241 standard is based on conformance with all normative parts that apply to a particular product.

Procurements must recognize the difference between informative and normative parts of the standard in question. Where possible, both the informative and normative parts should be required for the best implementation of modern human factors/ergonomic thinking. In general, conformance tests for informative parts will not be available.

The ISO and ISO/IEC standards cited in the gray area of the table are being balloted and revised at a rapid rate. Interested parties should monitor the progress of these standards at six month intervals to ensure they have the latest information. Offerers of products meeting existing or emerging standards should be required to provide a migration plan to ensure compliance of the products with the final standards documents.

The DOD HCI Style Guide is recommended, in particular section 3, which deals with hardware.

3.13.1.2 Human factors for keyboards. (This BSA appears in both part 3, User Interface, and part 13, Human Factors.) This BSA covers keyboard layout, including specific directions for layout of regions of the keyboard, and keyboard design. Ease of use and correct ergonomic design also are a part of this BSA.

3.13.1.2.1 Standards. Table 3.13-2 presents human factors standards for keyboards.

DODI 8120 mandates use of the DOD HCI Style Guide.

The ANSI X3.154 standard specifies the customary "QWERTY" keyboard arrangement. The ANSI X3.207 standard specifies the "DVORAK" keyboard arrangement. ACGIH is the American Conference of Governmental Industrial Hygienists.

3.13.1.2.2 Alternative specifications. There are no alternative specifications available.

3.13.1.2.3 Standards deficiencies. MIL-STD-1472D is in need of a comprehensive revision to update technical material so that it is reasonably consistent with the state of the art and to ensure that the two commands not currently using the standard can do so.

3.13.1.2.4 Portability caveats. No portability problems are known with the above specifications.

3.13.1.2.5 Related standards. The following standards are related to human factors standards for keyboards:

3.13.1.2.6 Recommendations. Procurements that require hardware components to be addressed by ergonomic standards can require conformance with standards for keyboards. Keyboard characteristics include keyboard height, slope, profile, surface properties, adjustability, bounce and character repeat, key positioning, key displacement and force, keytop shape, and keytop legends.

Parts 1 and 2 of the ISO 9241 standard (see related standards) are informative. Parts 2-9 are expected to be normative on completion. Conformance requirements for each normative part are embedded within that part. Conformance with the overall ISO 9241 standard is based on conformance with all normative parts that apply to a particular product.

Parts 1-8 of the ISO/IEC 9995 standard are normative. Conformance requirements for each normative part are embedded within that part. Conformance with the overall ISO 9995 standard is based on conformance with all normative parts that apply to a particular product.

The DOD HCI Style Guide is recommended, particularly for section 3, which covers hardware.

3.13.1.3 Human factors for non-keyboard input devices. (This BSA appears in both part 3, User Interface, and part 13, Human Factors.) This section presents human factors standards for input devices other than keyboards. These devices include trackballs, pens, and tablets among others.

3.13.1.3.1 Standards. Table 3.13-3 presents human factors standards for non-keyboard input devices.

DODI 8120 mandates use of the DOD HCI Style Guide.

3.13.1.3.2 Alternative specifications. There are no alternative specifications available. Research in this area includes a foot operated control for the cursor when the hands are occupied (nicknamed a "mole" in obvious derivation from "mouse").

3.13.1.3.3 Standards deficiencies. Deficiencies in the cited standards are not known.

3.13.1.3.4 Portability caveats. No portability problems are known with the above specifications.

3.13.1.3.5 Related standards. The following standards are related to human factors standards for non-keyboard input devices:

3.13.1.3.6 Recommendations. Procurements that require hardware components to be addressed by ergonomic standards can require conformance with standards for non-keyboard input devices. Ergonomic issues for non-keyboard input devices include keyclick, tracking speed, and on-screen ghosting of the pointer.

Parts 1 and 2 of ISO 9241 are informative. Parts 2-9 are expected to be normative on completion. Conformance with the overall ISO 9241 standard is based on conformance with all normative parts that apply to a particular product. Parts 1-8 of ISO/IEC 9995 are normative. Conformance with the overall ISO 9995 standard is based on conformance with all normative parts that apply to a particular product. Part 1 of the ISO/IEC 10741 standard is expected to be normative on completion.

Procurements must recognize the difference between informative and normative parts of the standard in question. Where possible, both the informative and normative parts should be required for the best implementation of modern human factors/ergonomic thinking. In general, conformance tests for informative parts will not be available.

The DOD HCI Style Guide is recommended particularly for section 3, which covers hardware.

3.13.2 Human factors for software user interfaces. This Mid level service area deals with human factors requirements for the software portion of the user interface.

3.13.2.1 Graphical user interface style guides. A GUI's style guide, which is part of the presentation management layer in the NIST's User Interface Reference Model, specifies a standard "look" for the GUI of an application to the user.

3.13.2.1.1 Standards. Table 3.13-4 presents graphical user interface style guides.

DODI 8120 mandates the DOD HCI Style Guide.

The Human-Computer Interface (HCI) Style Guide provides a common framework for HCI design and implementation with emphasis on standard look and feel for GUI based applications. Motif 1.2 is the current version of the OSF specification for GUI behavior and appearance and programming and data interfaces. It includes a style guide for GUI interfaces.

3.13.2.1.2 Alternative specifications. Several applicable consortia or de facto style guides are available for software user interfaces. These style guides promote consistency in user interface design across applications. However, conformance with one or more the style guides listed below does not guarantee conformance with ergonomic standards (e.g., ISO 9241). These style guides include:

3.13.2.1.3 Standards deficiencies. Currently, conformance to parts 12-17 of the ISO 9241 standard is on a part-by-part basis. There is concern that the overall standard may thus fail to address potential ergonomic problems arising from interaction between the user interface elements covered by the individual parts.

There is concern that ISO/IEC 11581 may contain overly rigid specifications for the set of icon shapes that can be used to represent different user interface parts.

3.13.2.1.4 Portability caveats. NIST FIPS 158-1 (User Interface Component of the Applications Portability Profile) mandates the use of the X Window protocol, X library, and X toolkit intrinsics. IEEE P1201.2, when completed, is intended to increase the level of user interface consistency (and thus user interface portability) across X Windows-based environments. There are potential conflicts here.

DOD HCI Style Guide is based on (and intended to supersede) the Army, Navy, Air Force, and DODIIS style guides cited in the table above. The goal of this effort is to minimize unnecessary user interface diversity across DOD systems. There are potential problems with systems designed to accommodate different style guides.

MIL-STD-1800 is an Air Force-only standard that duplicates MIL-STD-1472D and is largely ignored in Air Force acquisitions. It has been recommended that MIL-STD-1800 be canceled and any value added material be added to MIL-STD-1472D.

3.13.2.1.5 Related standards. The following standards are related to user interface style guides:

3.13.2.1.6 Recommendations. A style guide is necessary for development of all GUIs. There are no formal standards efforts in this area. A style guide is part of the Presentation Layer in NIST FIPS 158-1. Procurements that require software user interfaces to be addressed by ergonomic standards can require conformance with standards for menu structures, command languages, direct manipulation dialogs, forms-based dialogs, windowing, icons, screen formatting, information coding, and user guidance.

It is recommended that the practices of the DOD HCI Style Guide, TAFIM, Volume 8 be followed. It provides a common framework for HCI design and implementation with emphasis on standard look and feel for GUI based applications. As many aspects of standard GUI style are application specific, application area style guides should also be used when available. Motif 1.2 is the current version of the OSF specification for GUI behavior and appearance and programming and data interfaces. It includes a style guide for GUI interfaces and is also recommended.
Parts 1 and 2 of the ISO 9241 standard are informative; parts 10 and 11 are expected to be informative on completion. Parts 12-17 are expected to be normative on completion. Conformance with the overall ISO 9241 standard is based on conformance with all normative parts that apply to a particular product. The ISO/IEC 11581 standard is expected to be normative on completion.

3.13.2.2 Visualization. (This BSA appears in part 3, User Interface, and part 13, Human Factors.) Visualization is the method of displaying data in a graphical manner to aid in recognition of patterns and trends in data and to give the viewer a depiction of a physical system that has been modeled by data points (e.g., finite element analysis (FEA) and computational fluid dynamics (CFD)). Another technique is the visualization user interface (VUI), a GUI that interprets text and numbers as pictures to show their relative scales and other relationships. A VUI remodels data so that text and numbers are hidden behind a picture expressing their complex relationships. Engineering visualization is a term freely applied to almost any intersection where the engineering process meets image creation technologies.

3.13.2.2.1 Standards. Table 3.13-5 presents visualization standards.

3.13.2.2.2 Alternative specifications. There are no alternative specifications available, but extensive academic research on this topic is taking place, particularly in the University of Maryland's Human-computer Interaction Laboratory and the Software Psychology Society. Topics include using treemaps for visualizing hierarchical information, using statistical distortion to promote the detection of outlying data, and use of color coding as a visualization aid.

3.13.2.2.3 Standards deficiencies. Deficiencies in the existing standard are unknown.

3.13.2.2.4 Portability caveats. Portability problems with the existing standard are unknown.

3.13.2.2.5 Related standards. The following standards are related to visualization standards:

3.13.2.2.6 Recommendations. There are no recommendations for visualization itself, but it does require the use of power graphics generation if a dynamic system will be shown, rather than a series of static views. Other requirements can include a high degree of mathematical precision and single-pixel accuracy in rendering.

3.13.2.3 Color use. (This BSA appears in part 3, User Interface, and part 13, Human Factors.) The use of color is a vital part of communication with the user of computer applications. Computer representation of color is done through the use of the Red, Green, Blue (RGB) color separation method which must be used to approximate color definitions used in graphic technologies.

3.13.2.3.1 Standards. Table 3.13-6 presents standards for color use.

DODI 8120 mandates use of the DOD HCI Style Guide. The DOD HCI Style Guide addresses use of color and the meaning of color in section 4.3.

3.13.2.3.2 Alternative specifications. Alternative specifications include any user interface style guide that addresses the use and meaning of color.

3.13.2.3.3 Standards deficiencies. Comparison of color defined by the existing standards assumes identical viewing conditions. There are no standards directly addressing comparisons across viewing environments, although models are being worked on.

3.13.2.3.4 Portability caveats. Translation of color from one color definition system to another can be difficult and is only an approximation at best. There are three different color definitions from the CIE. They are CIEXYZ, CIELAB, and CIELUV. These standards have existed for a long time and are seen as the common basis for any future unifying definitions.

One problem with the use of color is color blindness. To accommodate the color blind, if color is used to convey important information, then a second method should also be used (such as brightness of the color).

3.13.2.3.5 Related standards. The following standards are related to human factors standards for the use of color:

3.13.2.3.6 Recommendations. The approved standards in this section are recommended where they are applicable. The DOD HCI Style Guide is recommended, particularly section 4.3 which addresses the use and meaning of color.

3.13.2.4 Color definition. (This BSA appears in part 5, Data Interchange, part 12, Multimedia, and part 13, Human Factors.) Color definition deals with establishing a reference base for identifying colors to aid in the matching and exchange of color. Color definition standards apply to defining color in general, and not only to color definition for information technology systems.

3.13.2.4.1 Standards. Table 3.13-7 presents standards for color definition.

The CIE (International Commission on Illumination) is the principal international standards writing body for agreements for color, vision, and illumination. Under ANSI, four bodies work on color-related standards. ANSI X3 works on office document automation and information systems. ANSI IT8/CGATS is concerned with graphic arts. ASTM deals with color metrology and standard practices, and SMPTE handles standards for color television and color monitors.

ANSI's Committee for Graphic Arts Technology Standards (CGATS) has eight subcommittees working on topics such as materials handling, process control, and color data definition. NPESA is the National Printing Equipment and Supply Association.

3.13.2.4.2 Alternative specifications. The following alternative specifications are also available:

3.13.2.4.3 Standards deficiencies. Comparison of color defined by the existing standards assumes identical viewing conditions. There are no standards directly addressing comparisons across viewing environments, although models are being worked on. Strict adherence to correct presentation and output standards will require color calibration equipment.

3.13.2.4.4 Portability caveats. Translation of color from one color definition system to another can be difficult and is only an approximation at best. There are three different color definitions from the CIE. They are the CIEXYZ tristimulus values, and the CIELAB and CIELUV color spaces. These standards have existed for a long time and are seen as the common basis for any future unifying definitions. There are also the problems of color matching. For example, of 1012 Pantone colors for coated paper, 70 cannot be reproduced in the CMYK definition. CIEXYZ is useful in comparing colors under identical viewing conditions. CIEXYZ has a rigorous definition and by itself does not necessarily constitute a complete color specification. CIEXYZ is a standardized set of primaries which are not physically realizable but can match all possible colors with entirely positive tristimulus values. A new form of color definition is emerging, known as high-fidelity color. The idea behind high-fidelity color is the use of five to seven different colors in the printing process to widen the range of colors that can be printed. Two such models that have appeared are the Kupper set which increases the number of printed colors in the blue region by 80%, and the VSF model which provides better performance in deep red and green colors. These processes are very non-standard and should be avoided at present.

Common systems typically do not support colorimetric calibration.

3.13.2.4.5 Related standards. The following types of standards are related to standards for the definition of color:

a. color matching standards
b. color data exchange standards
c. color use standards
d. style guide standards

3.13.2.4.6 Recommendations. The approved standards in this section are recommended where they are applicable. Maintain original copies of source material so that revisions can be produced for next generation systems that will allow the inclusion of calibration information.

3.13.2.5 Color data interchange. (This BSA appears in part 5, Data Interchange, and part 13, Human Factors.) This BSA deals with the specific problems of interchanging data about color in computer graphics.

3.13.2.5.1 Standards. Table 3.13-8 presents standards for color data interchange.

The Generic Architecture for Colour Data Interchange (GACDI) standard is a color architecture standard that will provide a consistent color framework across document-related standards. This standard will enable users to interchange color information in an open systems environment through the use of color data and transform representations.

3.13.2.5.2 Alternative specifications. No alternative specifications are available.

3.13.2.5.3 Standards deficiencies. There are no standards directly addressing comparison across viewing environments, although models are being worked on.

3.13.2.5.4 Portability caveats. Portability problems with the existing standards are unknown.

3.13.2.5.5 Related standards. Data interchange standards are related to standards for color data exchange.

3.13.2.5.6 Recommendations. The approved standards in this section are recommended where they are applicable.

3.13.2.6 Color matching. (This BSA appears in part 5, Data Interchange, and part 13, Human Factors.) This BSA deals with the problem of matching displayed and printed colors in computer systems.

3.13.2.6.1 Standards. Table 3.13-9 presents standards for color matching.

The ICC was formed in March, 1994, by Apple, Adobe, Silicon Graphics, Taligent, Agfa, Kodak, Microsoft, and Sun for the purpose of defining profiles for color handling. The ICC Profile format has no preferred color space, and provides for more than four input colors.

ColorSync Profile Consortium has adopted the CGATS.5 specification as its definition of colorimetry and color measurement.

The Open System Color Association (OSCA) has taken on the role of providing industry with a centralized, stable, reliable, and common source of certified color-calibration data. OSCA consists of Agfa, DuPont, Fujifilm, Kodak, Radius, 3M, and 24 other non-founding member companies. OSCA's work is in harmony with the ICC Profile format.

3.13.2.6.2 Alternative specifications. The following alternative specifications are also available:

3.13.2.6.3 Standards deficiencies. Comparison of color defined by the existing standards assumes identical viewing conditions. There are no standards directly addressing comparisons across viewing environments, although models are being worked on. The issue of where and how to correct color remains unresolved.

3.13.2.6.4 Portability caveats. Translation of color from one color definition system to another can be difficult and is only an approximation at best. There are three different color definitions from the CIE. They are CIEXYZ, CIELAB, and CIELUV. These standards have existed for a long time and are seen as the common basis for any future unifying definitions.

Because of their display orientation, all standards that are defining computer generated graphics color, use RGB models. Most programmers assume that the RGB values they are using are linear with display intensity and that may be approximately true depending on the response of the graphics system. The actual colors produced vary according to the graphics system used.

3.13.2.6.5 Related standards. Color definition standards are related to human factors standards for color matching.

3.13.2.6.6 Recommendations. The approved standards in this section are recommended where they are applicable.

3.13.2.7 Customization to local norms. (This BSA appears in part 3, User Interface, part 13, Human Factors, and part 14, Internationalization.) Customization to local norms involves modification of the key mapping to accommodate the local language and display of data in the commonly-used format (e.g., numbers, dates, time).

3.13.2.7.1 Standards. Table 3.13-10 presents standards for customization to local norms.

DODI 8120 mandates use of the DOD HCI Style Guide

Motif 1.2 is the current version of the OSF specification for GUI behavior and appearance and programming and data interfaces. X11R5 is the current release of Version 11 of the X Windows standard.

3.13.2.7.2 Alternative specifications. Several applicable consortia or de facto style guides are available for internationalization. However, conformance with one or more the style guides listed below does not guarantee conformance with ergonomic standards:

3.13.2.7.3 Standards deficiencies. Currently, conformance to parts 12-17 of the ISO 9241 standard is on a part-by-part basis. There is concern that the overall standard may thus fail to address potential ergonomic problems arising from interactions between the user interface elements covered by the individual parts.

3.13.2.7.4 Portability caveats. Although Motif supports the X/Open Native Language System, it also supports a number of its own internationalization extensions which makes it incompatible with some legacy specifications (e.g., OpenLook).

NIST FIPS 158-1 (User Interface Component of the Applications Portability Profile) mandates the use of the X Window protocol, X library, and X toolkit intrinsics. IEEE P1201.2, when completed, is intended to increase the level of user interface consistency (and thus user interface portability) across X Windows-based environments. There are potential conflicts here.

The DOD HCI Style Guide is based on (and intended to supersede) the Army, Navy, Air Force, and DODIIS style guides cited in the table above. The goal of this effort is to minimize unnecessary user interface diversity across DOD systems. There are potential problems with systems designed to accommodate different style guides.

3.13.2.7.5 Related standards. The following standards are related to cultural convention services:

3.13.2.7.6 Recommendations. Procurements that require software user interfaces to be addressed by ergonomic standards can require conformance with standards for menu structures, command languages, direct manipulation dialogs, forms-based dialogs, windowing, icons, screen formatting, information coding, and user guidance.

Parts 1 and 2 of the ISO 9241 standard are informative; parts 10 and 11 are expected to be informative on completion. Part 3 of the ISO 9241 standard is normative; parts 2-9 and 12-17 are expected to be normative on completion. Conformance with the overall ISO 9241 standard is based on conformance with all normative parts that apply to a particular product.

Procurements must recognize the difference between informative and normative parts of the standard in question. Where possible, both the informative and normative parts should be required for the best implementation of modern human factors/ergonomic thinking. In general, conformance tests for informative parts will not be available.

The DOD HCI Style Guide is recommended for customization to local norms.

3.13.3 Human factors for computer environments. This Mid-Level Service Area addresses the environment as it affects both the user and the computer.

3.13.3.1 Human factors for the physical environment. (This BSA appears in both part 3, User Interface, and part 13, Human Factors.) Procurements that require computing environments to be addressed by ergonomic standards can require conformance with standards for illuminance, glare, acoustic noise, the thermal environment, electromagnetic emissions, computer workspace design and furniture design.

The effects of low-level non-ionized radiation, particularly from CRTs, on humans have been a controversial topic. Over the years there have been articles advising pregnant women who have a prior history of miscarriage to stay away from working in computer areas. During the cold war, the Soviets were suspected of secretly bombarding foreigners with non-ionized radiation to study long term effects. People who live near high voltage power lines and have developed cancer are suspected victims of electromagnetic radiation. While there are no hard theories to describe the relationship between health problems and this kind of radiation, let alone a standard established. Some VDT vendors have made claims regarding the emissions of their products and there are aftermarket shields available that may provide some protection against this form of radiation.

Laser printers are said to emit ozone during the printing process. In an enclosed area, high levels of ozone can be unhealthy or even toxic. This issue is still unclear. It remains to be seen how much ozone is emitted and what concentrations are hazardous.

3.13.3.1.1 Standards. Table 3.13-11 presents human factors standards for the physical environment.

DODI 8120 mandates use of the DOD HCI Style Guide.

3.13.3.1.2 Alternative specifications. MPR II 1990:8 (Test Methods for Visual Display Units, Section 2.0.1) is a Swedish document containing recommended values for electronic emissions from visual display units. While not an ISO standard, it serves as a de facto electromagnetic emissions standard for displays in most other countries. Many vendors of monitors claim compliance with this or a similar specification. After-market radiation and glare shields are also available.

3.13.3.1.3 Standards deficiencies. Deficiencies in the existing standards are unknown.

3.13.3.1.4 Portability caveats. MIL-STD-1474C's criteria are more stringent than those of the Occupational Safety and Health Administration and also covers additional topics such as nondetectability. This standard may be incorporated into the next revision of MIL-STD-1472, eliminating the need to retain MIL-STD-1474C.

3.13.3.1.5 Related standards. The following standards are related to human factors standards for computer environments:

3.13.3.1.6 Recommendations. The approved standards in this section are recommended where they are applicable. Parts 2-9 and 12-17 are expected to be normative on completion. Conformance with the overall ISO 9241 standard is based on conformance with all normative parts that apply to a particular product.

The DOD HCI Style Guide is recommended particularly for section 3, which covers hardware.