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Effective Warnings

A warning is one means for preventing injury incidents. Other methods are better. The best way to prevent injury incidents is to design the product or job or environment so a hazard does not exist. When this is not possible, then people should be guarded from the hazard, or trained to avoid the hazard. However, when a hazard in a product, job, or environment cannot be eliminated, using warnings can be effective in preventing injury incidents.

Effective warnings include the following four components:
  • Signal word.  Signal words DANGER, WARNING or CAUTION indicate that a hazard is present
  • Description.  A concise and specific description of the hazard
  • Consequences.  Specific description of the consequences of failing to comply with a warning
  • Instructions.  Instructions for what the reader can do to avoid the hazard

Effective warnings are presented with the following characteristics:
  • Placement.  Positioning near the hazard, when it is needed
  • Color.  Red, orange, yellow; Red is detected more quickly and indicates a greater hazard level
  • Visual emphasis.  Borders and highlighting help attract attention to the warning sign
  • Layout. The arrangement of the warning components affects understanding and compliance
  • Symbology.  Icons and pictorials attract attention and improve compliance

Behavioral issues that affect compliance with warnings:
  • Familiarity.  Familiarity with a situation or product may result in failure to comply with warnings
  • Perception.  A perception of low hazard may result in failure to comply with warnings
  • Control.  Belief in one's control of the risks may result in failure to comply with warnings
  • Cost. A high cost in time or effort to comply with a warning may result in failing to heed it

• What we do:
Our experience and knowledge of human factors engineering, as well as warnings standards (such as those from ANSI), enables us to evaluate the effectiveness of warnings in a variety of situations.

• Example cases:
Cases have included hazard warnings for medical products, industrial equipment, and built environments.

 Forensics human factors articles on warnings from HFE Consulting.

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