David Hemenway is Professor of Health Policy at the Harvard
School of Public Health, Director of the Harvard Injury Control
Research Center, and Director of the Harvard Youth Violence Prevention
Center. His previous books include Private Guns, Public Health. Hemenway is also the author of While We Were Sleeping: Success Stories in Injury and Violence Prevention, which was published by UC Press in March 2009. In his blog entry below, Hemenway discusses how research helped change policies in public health.
Public Health Research and Injury Prevention
By: David Hemenway
I describe more than 30 public health heroes in While We Were Sleeping. Almost all of these individuals were activists, who struggled to make the world safer—and succeeded. But I feel a little bad, because I barely mention the injury experts and researchers who also do such important work. So last year when I gave a talk about the book to an audience of injury researchers at an international conference in Mexico, I emphasized how data and research studies were critical for most of the successes.
Data and research are crucial for (1) documenting the problem, (2) targeting policies and (3) evaluating the interventions. Here are a couple of examples from just one injury area—motor vehicle crashes.
Graduated Drivers Licensing: Young drivers are very dangerous. Data showed that 16 year-old drivers had almost ten times the crash risk of 40 year-olds, and almost three times the crash risk of 19 year-olds. One reason for the higher risk was lack of experience, but the way to gain experience was by driving. What was needed was a way to gain experience while minimizing risk. Research also showed that young drivers were at particularly high risk (a) during the first few months of driving, (b) at night, and (c) when other young people (and no adults) were in the car. So graduated licensing systems were created to allow youth driving, but limit their driving in these high-risk situations. Studies of states that initially adopted these systems showed such large benefits (e.g., 30% decreases in injuries and death) that within a decade every U.S. state adopted Graduated Licensing.
Third Brake Light: Data showed that rear-impact collisions accounted for more than 20% of all collisions. In the late 1970s, in scientific trials with taxicab and telephone company passenger cars, a random sample was provided with center, high-mounted brake lights. Those cars with the new brake light were rear-ended about half as often as cars without the third brake light. Based on these studies, the federal government mandated a center high-mounted stop lamp on all new passenger cars. Studies find that this requirement prevents some 25,000 motor vehicle injuries per year.
One of my favorite injury prevention heroes is John Paul Stapp (1910-1999). A physician and Air Force colonel, in the 1950s he became the fastest man on earth, traveling faster than a speeding bullet. Using himself as a human guinea pig, on a test track in New Mexico in 1954, Stapp strapped himself in for his twenty-ninth and final sled ride. In five seconds he accelerated to 632 mph, then was brought to a complete halt—in 1.4 seconds. He suffered (temporarily) complete red out, as nearly every capillary in his eyeballs burst. But his feat showed that humans could tolerate more than 25Gs, and that air force cockpits needed to be re-designed so that pilots would survive such a deceleration.
Stapp became an instant celebrity, featured on the cover of Life magazine and in a Hollywood movie. He used his fame to promote automobile safety. He even persuaded the Air Force to build an automotive testing facility, and he conducted the first-ever crash tests using dummies. How did he persuade the Air Force to spend so much money on automobile safety? By providing data and studies showing that more Air Force pilots were being killed in traffic accidents than in plane crashes.
Data and research are key to policies that improve safety. While my book hardly discusses the work of injury control researchers, there is little doubt that good data and good science typically provide the foundation for endeavors that successfully save lives.