Study shows wearing life jacket significantly increases odds of surviving recreational boating accident

raystown8-15-03

Requiring recreational boaters to wear life jackets would increase their odds of surviving an accident by 80 percent, according to a recent research study conducted at the University of Maryland Baltimore County in collaboration with the U.S. Coast Guard. In addition, life jacket effectiveness is at its peak when the watercraft is short: The odds of incurring a fatality are 86% higher than average if the accident involves a canoe or kayak.

NC_Wear It! (2)Although watercraft are required by law to carry life jackets, boaters often fail to use the flotation devices because they find them uncomfortable or believe that wearing one suggests inexperience as a boater or limited swimming ability. Many boaters will use life jackets only when conditions on the water are poor. Survey participants have suggested that manufacturers design better-fitting, more appealing devices; but the new study raises the question of whether mandatory life jacket use may be needed to change boaters’ habits.

The study contributes to the research that would be necessary to implement what would be a far-reaching and controversial policy of mandating life jacket use. Its primary objective is to assess the impact of a life jacket policy on the recreational boating fatality rate. “However, such a major and controversial policy cannot be implemented without a thorough investigation of life jacket effectiveness. A lot of the work focusing on reducing recreational boating fatalities lacked the availability of life jacket use data,” the authors write, indicating that their study rectifies that deficiency.

The study—“An empirical analysis of life jacket effectiveness in recreational boating”—was conducted by Dr. Christelle Viauroux, an economics professor of the University of Maryland–Baltimore County, and Ali Gungor of the U.S. Coast Guard’s Standards Evaluation and Analysis Division. The study appeared in the online version of Risk Analysis, a publication of the nonprofit Society for Risk Analysis, a multidisciplinary, interdisciplinary, scholarly, international society that provides an open forum for all who are interested in risk analysis.

Using data for the years 2008 to 2011 from the U.S. Coast Guard’s Boating Accident Report Database (BARD), the researchers explain the number of fatalities and their variation across types of vessels. They measure the effect of life jacket use relative to other significant environmental and individual factors affecting fatalities in recreational boating accidents.

MO_paddleboarding-in-virgin-islandsViauroux and Gungor predict, based on their analysis, that if boaters wore life jackets, the number of deaths from boating accidents could be cut by about 80 percent. In addition, they conclude that the odds of dying are 86 percent higher than average if the accident involves a canoe or kayak, but 80 percent lower than average when more than one vessel is involved in the accident and 34 percent lower than average when the operator involved in the accident has more than 100 hours of boating experience. While combining multiple factors that were present during an accident, life jacket wear is therefore estimated to be one of the most important determinants influencing the number of recreational boating fatalities.

The study also investigates the combined effect of life jacket wear and blood alcohol concentration on the number of fatalities. Results show that when taken separately, without any other environmental factors included, both life jacket wear and blood alcohol concentration are significant in explaining the number of deceased in an accident: a 67 percent increase in the odds of dying when the operator does not wear his/her life jacket and a 28 percent increase in those odds for every 10 percent increase in operator’s blood alcohol concentration. 

However, when including both factors simultaneously to explain the number of fatalities, results show that blood alcohol concentration becomes insignificant. Viauroux and Gungor explain that “it is possible for a factor to significantly affect the number of fatalities when it is seen as the unique explanation of the outcome but become insignificant when other factors are introduced because some of its effect is subsumed by one or more other variables”, implying that operators who do not wear their life jacket may include those drinking excessive alcohol.

The authors find other factors that influence the accident outcome to a lower extent. For example, speed and watercraft engine power are found to have a statistically significant effect on the number of fatalities: the average number of deceased is about 57 percent higher when the vessel is not moving at the time of the accident and is 65 percent lower when the vessel averages a speed of 10 to 20 miles per hour in contrast to higher speeds. The number of fatalities is also estimated to be 5 percent lower for each additional foot of watercraft length and 77 percent higher when the watercraft has two engines compared to a watercraft with only one.

Viauroux and Gungor also note that the average number of deceased is 40 percent lower when the accident occurs during the day and is estimated to be about 25 percent higher when the accident occurs during a weekday as opposed to a weekend.

Among minor factors, the authors find operator’s age to be slightly positively correlated with the number of deaths observed: It increases about 1 percent for every additional year of age of the operator. This result may capture unobserved characteristics of the operator such as overconfidence or high risk taking as experience increases. This intuition is consistent with another result on boat rentals. Viauroux and Gungor find that the number of deceased is 22 percent lower when the boat has been rented. In this case, the less experienced operator may be more risk averse, perhaps making overall fewer life-threatening mistakes. Furthermore, the lower number of deceased may also be due to the fact that rented boats may be in better condition and that renters may require life jacket wear.

life jacket collageNot surprisingly, environmental conditions are found to slightly change the accident outcome, with each additional degree Fahrenheit in water temperature decreasing the average number of fatalities by about 1 percent. Furthermore, this effect varies greatly depending on operators’ willingness to wear their life jacket: life jacket effectiveness is estimated to be much higher in cold water, perhaps reflecting the debilitating effects of cold shock.

Through their research, the authors found that between 2008 and 2011, a life jacket regulation requiring all operators to wear their devices—representing a 20 percent increase in the current wear rate—“would have saved 1,721 (out of 3,047) boaters or 1,234 out of 2,185 drowning victims. The same policy restricted to boats 16 to 30 feet in length would have saved approximately 778 victims.” Finally, such a policy “would reduce significantly the percentage of drowning victims compared to other causes of death,” the authors conclude.

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