Our expertise

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.

How we help

Cases have included failure to warn in public, commercial and industrial settings, with issues involving content and placement of environmental, equipment, and product warnings.

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

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

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

Example cases:

Cases have included hazard warnings for medical products, industrial equipment, and built environments.

Environmental warning

Twenty-five-year-old theme park patron entered area beneath suspended roller coaster to retrieve the hat his wife had dropped previously while riding the roller coaster. While retrieving the hat, the roller coaster passed overhead and the leg of one of the passengers struck him in the head, killing him. The passenger sustained substantial injuries to her leg.

A warning sign was placed on the fence surrounding the area beneath the roller coaster. The sign said “DANGER. RESTRICTED AREA. AUTHORIZED PERSONNEL ONLY”. The sign was printed only in English. The sign included text and no pictorial. The deceased patron neither spoke nor read English.

The plaintiff’s attorney retained the human factors expert. After the expert read the ride operation and safety manuals, read depositions, reviewed diagrams of the ride, and conducted a site inspection, he provided deposition and trial testimony on human factors design issues, visual perception and cognition, human information processing, and safety practices. The testimony included information about the presentation and content of effective warnings, as well as the behavioral issues in responding to the perceived hazards in the environment. Case settled during trial.

Product warning

Forty-seven-year-old man with diabetes used a heat pack to soothe aches on one of his feet, which resulted in severe burns to that foot. His occupation required that he walk during the entire work day. He missed six months of work.

Plaintiff says he read the instructions and did not see any warnings about use.

The plaintiff’s attorney retained the human factors expert. After expert read depositions, examined the warning on the product, and interviewed the plaintiff and his wife, he provided a verbal report to the attorney regarding warnings. The case was settled before deposing expert.