This part of ISO 9241 provides guidelines to users of VDT-based information processing systems with reference to office tasks. This guidance is relevant to both the organization implementing the system and the people using the equipment. The guidance should be applied in accordance with local, regional or national agreements and regulations. The objective of this part of ISO 9241 is to enhance the efficiency and well-being of the individual user by applying ergonomics knowledge in the light of practical experience, to the design of tasks. The ergonomics principles concerned are set out in ISO 6385. The characteristics of the visual display, and the control, workplace and environmental requirements are specified in other parts of ISO 9241. This part of ISO 9241 does not address software and dialogue design.