Greetings from a guest columnist and Exponent colleague of Dr. Richard Martin. I am a scientist with 20 years of experience investigating human behavior. I conduct research in areas related to human learning, perception, memory, decision-making and information processing. As a human-factors consultant, I focus on the cognitive factors that affect risk perception and safety, including hazard communications such as labels, signs and instruction manuals. This column aims to highlight some considerations for the safety-minded manager from a human-factors perspective.

The arrival of the summer season brings changes to every workplace. For example, there is more frequent vacationing, leading to more workers covering unfamiliar positions and performing unfamiliar tasks; there is sometimes less supervision; and there are larger numbers of inexperienced employees – such as teenagers – present in the workforce.

Not surprisingly, national injury statistics reflect these and other factors. Unintentional injuries in the U.S. peak in the months of June and July. Some of these injuries are associated with school-age children having increased exposure to hazards at home and/or in recreational settings, but occupational injuries also increase. One study reported that over 40% of annual occupational electrocutions occur in the months of June, July and August. It stands to reason that enhanced safety-related vigilance in the late spring and summer months could provide an extra payoff.

Safety managers are often concerned with identifying the degree to which specific incidents are attributable to human operator error versus some feature of design or manufacture. But preventing future incidents is also a priority. Human error accounts for the vast majority of industrial and other accidents. For example, over 90% of motor-vehicle accidents have operator error as a contributing factor. Thus, a reduction in accident rate due to the avoidance of errors requires an approach that accounts for human reasoning and decision-making.

An examination of published data reveals that the range of error rates in industrial settings is broad. Some errors occur during the performance of simple manual repetitive tasks, whereas others are more likely to involve more complex information processing and decision-making. Of course, errors are not always associated with injury, but among those that are, risk perception and decision-making are important contributing factors. The reduction of injury-related error requires an analysis of the types of errors involved and the degree to which enhancements in training to improve skill or awareness of risks may contribute to improved risk perception and safety mindedness.

Even under conditions in which training is adequately administered, workplace safety is dependent on many factors including the environment (lighting, weather) and exposure to hazards (pinch points, rotating parts). In addition, stress, fatigue and other impairment-related factors are known to have a detrimental influence on individual performance. An understanding of the degree to which the environment and individual impairment may affect a person’s ability to draw on their training or to retain a safety-minded attitude is important. Such an analysis would take into account basic human capabilities and limitations in terms of information processing, memory, decision-making and response selection, movement execution and preparation.

Although it is easy to imagine circumstances in which a new summer intern could make a safety-related mistake, it is also important to remember that some errors may be due to the behavior of experienced workers (e.g., removing safeguards, following shortcuts for personal convenience). The reduction of these behaviors may be best served through a combination of training and credible enforcement. Note, however, that training may be of limited impact when the subjects of that training consider themselves to be already well informed through personal experience. Therefore, incentives for improved safety mindedness should be provided to more experienced workers.

Ultimately, attention paid to managing errors and accidents during the summer period could pay disproportionate dividends in terms of the overall annual safety performance. In addition to considering the above factors, employers may take advantage of materials specifically geared towards increasing summer safety, such as those offered through the OSHA Teen Summer Job Safety Campaign (

Of course for a summer program to be most effective, organizational structure and processes that support management of accident risk year-round should be in place.IH