Human factors and ergonomics discovers and applies information about human behavior, abilities, limitations, and other characteristics of the design of tools, machines, systems, tasks, jobs, and environments for productive, safe, comfortable, and effective human use. In this context, human factors and ergonomics deals with a broad scope of problems relevant to the product design and evaluation of work systems, consumer products, and working environments in which human-machine interactions affect human performance and product usability.
In the field of safety, human factors and ergonomics there is a hazard control hierarchy that is used to reduce the likelihood and severity of injury. This hierarchy consists of an ordered set of approaches or procedures for dealing with potential hazards during the product design.
The key elements in this sequence are:
- Design out the hazard
- Guard against the hazard
- Warn of the hazard
One of the main purposes of instructions and warnings is to inform all foreseeable users. Warnings can fill in gaps of knowledge about foreseeable or hidden hazards and remind us of hazards which otherwise may have been forgotten. Warnings should be understandable and sufficiently explicit so that the persons at risk will be informed about the hazards and potential consequences if they fail to comply with its directives. In the context of dealing with hazards, it is not enough to say that people should know something. Rather, it is critical that people be made aware of the relevant information at the right time. Warnings serve as reminders or cues which help us access that information stored in memory in order to make appropriate decisions. Warnings are not expected to serve as a cure for bad design. A warning should include everyone who may be exposed to the hazard (who are at risk) and everyone who may be able to prevent and adverse outcome.
The presentation principles of instructions and warnings are based on human factors and ergonomics principles of how people access, process and use information. Instructions and warnings should be presented explicitly, concisely and in a way that is readily understood so that potential users can comprehend and make appropriate decisions regarding proper use and safety.
In order for warnings and instructions to be effective, they must be easily identified by the user. Warnings and instructions should be designed to include everyone who may be exposed to the hazard (who are at risk) and everyone who may be able to do something about it. If specific user groups are at a higher risk of injury, the user groups should be adequately instructed of the potential hazard.