Expert Article Library

The Human Factors Expert

by Joseph Cohen & H. Harvey Cohen

It is not uncommon for attorneys representing clients in legal proceedings to speak to a human factors expert about liability and other issues. Oftentimes attorneys call our office because someone has told them they needed a “human factors” expert or because the opposing attorney on a case has engaged a human factors expert. If he/she is unfamiliar with human factors as a field, the call will inevitably lead to the questions, “Just what is human factors, anyway, and how can expertise in human factors help my case?”

What is human factors, anyway?

Human factors is a multi-disciplinary field grounded in the behavioral and engineering sciences. Human factors/ergonomics takes into account human physiology and behavior in the design and maintenance of a variety of products, equipment, facilities, jobs, tasks and overall organizations. In practice, its methods are applied to maximize human performance as well as determine the causes and means for the prevention of injuries, with emphasis placed on how people interact with their environments. Human factors is synonymous with ergonomics and is commonly referred to as such by industries throughout the world. We define forensic human factors/ergonomics as the application of the science of human factors/ergonomics to situations in the legal setting. Similar to traditional human factors/ergonomics applications and systems design, the analysis is human-centered, focusing on identifying and offering solutions to correct situations and conditions that exploit shortcomings in human performance. That which is unique to the practice of forensic human factors/ergonomics is its application to legal issues.

Living in modern society requires that we take precautions to ensure that our actions (and inactions) do not harm other people or their property. As such, western civil law is concerned with standards of reasonable care. People are held to the same objective standard, despite their shortcomings, using a yardstick, “the man of ordinary prudence.” Therefore, in forensic settings we define human factors as the science of establishing reasonable care in the design, maintenance, and use of products, equipment, and facilities. Establishing standards of reasonable care is what makes the field of forensic human factors/ergonomics unique from not only other application areas of human factors/ergonomics, but from other forensic sciences or disciplines.

What kinds of cases are suited for human factors experts?

Historically, individuals with expertise in forensic human factors consult more often in matters of personal injury law (civil) rather than criminal legal proceedings. Cases in which human factors experts are retained typically involve consumer products, premises, or transportation systems, although these categories are not mutually exclusive.

Premises liability. In our experience, the largest focus of investigations regarding premises has been directed to the prevention or mitigation of fall injuries. This is not surprising considering the high relative frequency and severity of such incidents, second only to motor vehicle collisions. Specific premises incidents addressed by qualified human factors/ergonomics professionals include:

• Falls on level surfaces (e.g. slips, trips, missteps, slipperiness, hazard visibility/conspicuity); • Falls from elevated surfaces (e.g. stairs, ramps, ladders, work platforms, vehicle ingress and egress, handrails, and guardrails); • Biomechanics (normal and disrupted gait, fall dynamics); and

Information-processing (eye scanning patterns, focus of attention, sensory cues, competing stimuli, task loading, user expectations, impairments). Typical systems issues in these applications are the design, construction, maintenance, and use of the premises, as well as in various products and transportation systems.

Products liability is an area of law in which individuals with expertise in human factors make significant contributions. The most commonly addressed areas are alleged product design defects, manufacturing defects, and failures to warn. Defects oftentimes involve core human factors/ergonomics principles affecting a user’s reasonable expectations about products and their use(s). The human factors/ergonomics approach in product cases focuses on the hierarchy of controls which specifies that dangerous features first be designed-out of the product or, second, protected by shields or guards. Warnings, instructions, and/or training addressing proper use and any foreseeable misuse are required if the other two options are not possible.

Transportation systems. Transportation systems design and safety have been studied by human factors/ergonomics professionals since the field’s origin. Human factors/ergonomics applications have evolved to include air transport, motor vehicles, industrial and commercial vehicles, rail and water transport, and recreational vehicles. Individuals with expertise in human factors/ergonomics typically consult on cases involving collisions between two or more motor vehicles (cars, trucks, etc.), between motor vehicles and individual means of transport (motorcycles, bicycles, etc.), as well as between motorized transport and pedestrians. In most cases, human factors/ergonomics practitioners are qualified to offer expert opinions on such specific issues as visibility/conspicuity, perception–reaction, attention demand, skill level, human error, impairments to performance and decision-making.

How can expertise in human factors help my case?

Human factors/ergonomics professionals help determine the scientific basis behind the success or failure of standards of care in litigation. Additionally, since the field of human factors/ergonomics is concerned with how people interact within their environments, individuals with expertise in this specialty area provide valuable testimony in assisting the trier of fact in deciding whether a particular conduct met or breached the legal standard of care. Testimony from qualified human factors/ergonomics professionals with the pre-requisite education, training, certifications, and experience can be used to demonstrate that breaches of the standard of care caused the damages to another party. Despite its apparent utility for attorneys, it should be noted that human factors/ergonomics cannot address the issue of whether a legal duty is owed and the monetary extent of the damages incurred. Notwithstanding, through the use of human factors/ergonomics investigation and testimony, standards of reasonable care in various situations and contexts are being further developed, evaluated, and refined within the legal system and in the interests of public safety.