Overview
SIST EN ISO 9241-420:2011 (ISO 9241-420:2011) is part of the ISO 9241 series on ergonomics of human–system interaction. It provides guidance for the selection of physical input devices for interactive systems based on ergonomic factors, the capabilities and limitations of users, the tasks to be performed and the context of use. The standard covers selection methods and evaluation aids (including tables and test procedures) but does not prescribe design requirements for devices.
Relevant input devices covered include: keyboards, mice, pucks, joysticks, trackballs, trackpads, tablets and overlays, touch-sensitive screens, styli and light pens. It is intended primarily for user organizations and systems integrators tailoring systems for specific contexts of use.
Key Topics and Requirements
- Selection procedures and rationale - principles for choosing one device or a combination of devices to match user needs, tasks and environment.
- Methods and aids - documented approaches such as:
- Task analysis to map user goals and task primitives to device capabilities.
- Selection based on product description using normative tables and checklists.
- User tests and usability evaluations to validate selection under realistic conditions.
- Selection based on dominant task primitive(s) when specific subtasks dominate interaction.
- Special guidance for selecting keyboards and other device-specific considerations.
- Performance criteria - guidance on what to assess (e.g., appropriateness, operability, controllability, biomechanical load), without specifying numeric thresholds.
- Field assessment methods - approaches for in-situ evaluation and assessing acceptability of trade-offs.
- Informative and normative annexes - practical test procedures (tracing, dragging, tapping, mobile text entry), comfort assessment, and detailed device-selection tables (Annex H).
Practical Applications
- Procurement and specification - generate ergonomics-informed selection criteria for purchasing input devices.
- System integration and configuration - choose device combinations suited to user populations and operational contexts (control rooms, mobile work, assistive settings).
- Usability testing and validation - run device-focused user tests and field assessments to confirm acceptability.
- Risk reduction and ergonomics compliance - reduce biomechanical load and usability problems by matching devices to tasks and users.
Who should use this standard
- User organizations (enterprises, public services) selecting devices for staff
- Systems integrators and solution providers configuring interactive systems
- Ergonomists, HCI designers and usability professionals advising on input-device fit
- Procurement and health & safety teams evaluating ergonomic trade-offs
Related standards
ISO 9241-420:2011 sits within the ISO 9241 ergonomics family; users often consult other parts of ISO 9241 for broader usability, visual display, and software interaction guidance.
Keywords: ISO 9241-420:2011, ergonomics, input device selection, human-system interaction, keyboards, mice, touchscreens, usability testing, task analysis.