Principles of Injury Prevention
Before we talk specifically about identifying strategies, I'd like to say just a couple of words about some of the principles of injury prevention. Part of this will be a review of the material that has been presented in other sections.
Injuries are preventable
The first and possibly the most important principle that you've heard repeatedly from Dr. Runyan (Chapter Two and Chapter Four) and Dr. Rosenberg (Chapter Three) is that injuries are preventable. They're preventable because there's an epidemiology or a pattern to injuries. Through studies done by injury researchers we can come to understand patterns of injuries. These patterns make injuries foreseeable and preventable. Once we know what to expect we can begin to think about how to intervene in order to prevent injuries from occurring.
Injury prevention is a science
Another principle to keep in mind is that there's a science to injury prevention. That may sound very simple, but actually I think it's a terribly important principle to remember. Whenever I talk about whether there's a science to injury prevention I think about a newscast that I saw in Baltimore. Two co-anchors were telling a story about a roadway that goes from the Baltimore airport up into the city of Baltimore. This was a six-lane highway with a speed limit of 55. At some point along the road there's a housing area on one side of the road and stores on the other. It's not uncommon to be driving on this road and see someone trying to dash across. The newscast that night described someone who did try to run across that road and was struck and killed by a fast moving vehicle. This information was conveyed to the viewers as a part of the newscast.
After telling the story, one of the newscasters turned to the other and said, "It seems like we keep hearing stories about people being injured or killed on that highway. What do you think is going to happen?" The second newscaster looked at the camera and said, "I guess the community is just going to have to experience several more deaths before they understand that this is a dangerous situation."
Where does an opinion like that come from? What's missing there is the science of injury prevention. It was informative that the story right after the pedestrian death story was one about infant deaths that occurred as a result of an infectious disease in a newborn nursery at a hospital. After this story, one newscaster didn't say to the other, "What do you think the antibiotic of choice would be to use in that kind of a situation?" I expect that if he had done that, the second newscaster would have said, "What are you asking me for, I'm not an expert." The point to be made here is that there is a science to injury prevention. The choice of interventions to prevent pedestrian deaths or any other kind of injury death should be informed by that science.
The choice of interventions should be driven by people trained in the science of injury prevention. People have been studying how to prevent injuries for quite some time now and we've learned a lot about injury prevention. We know now that all prevention techniques are not alike and that all prevention techniques are not equally likely to be effective. We have to know something about how to choose the appropriate technique for a given problem. All of that deals with the science of injury prevention. It's important for us to remember that not all opinions about injury prevention are equal. People going through this course will be trained in injury prevention and, as a result, will become more expert in understanding how to prevent injuries. By understanding the science of injury prevention, you'll be much more capable of successfully preventing injuries than someone making decisions based on uninformed opinion.
Objections to injury prevention
Another principle to keep in mind with regard to injury prevention is that there will always be somebody available to object to the strategy that you've chosen to use. For example, objections will come on the basis of cost-benefit analysis. Someone might say, "This is going to be a very costly intervention and we don't really know how many lives we're going to save, so we don't know if it's really worth that kind of intervention." It's also an issue of who's paying the cost. There's something about injury prevention that makes cost a difficult topic to discuss. When we talk about prevention, we're talking statistically, about the lives of people we don't know. If we knew whose life we were going to save then we would probably be willing to spend any amount of money to save that life. With true prevention, however, you don't know whose life is going to be saved so cost becomes a very important factor.
There are also other objections that will come up with regard to injury prevention. One example is the important balance that exists between injury prevention and individual liberties. Sometimes we step on people's freedom when we're trying to prevent injuries. A good example of this is the example given earlier of motorcycle helmet legislation. We know that motorcycle helmet legislation will put helmets on people's heads. Therefore, we know that motorcycle helmet legislation is likely to bring down death rates among motorcyclists, particularly from head injuries. We also know, from the courts, that legislation requiring motorcyclists to wear helmets is constitutional. There's no doubt about that. In fact, the United States Supreme Court, in reviewing the ruling of a lower court, agreed with this idea on the basis that society shares in the cost of motorcyclists' injuries, particularly head injuries. There's a real societal interest in preventing those costs. It's not just the motorcyclist's head that's at risk; the court has said it's also our pocketbooks that are at risk.
But not withstanding the fact that these laws are going to work and that they're constitutional, we've still seen states repeal motorcycle helmet laws. These helmet laws were put into effect when the Federal government said that they would withhold highway funding from states if states didn't have helmet laws. When that decision was reversed, however, so that states were able to repeal their laws without a loss of funding, a majority of the states in the US either repealed or materially weakened their motorcycle helmet laws. The result was that motorcyclists' death rates went back up. The motorcycle helmet law is an example of a law that, while we know it to be effective, some people still say should not be passed because it is perceived as infringing on personal liberties.
Strategies: The Haddon Matrix
In addition to this temporal sequence, Dr. Haddon said there are other factors involved in injury occurrence. For instance, there's the host or the person who's involved in the injury, and the equipment that's involved in the injury. There are also different environmental situations, physical and social, in which an injury might take place. When you put these two axes together you get a matrix called the Haddon Matrix. This is generally a twelve-cell matrix although it can be a nine-cell matrix if the physical and social environment rows are combined into one.
The value of the Haddon Matrix is that it points out different areas in which interventions can be mounted. It used to be thought that the host/ pre-event cell was the one on which people should focus most attention. The content of that cell would have been teaching people to be cautious in their behavior in order to avoid injury. But it would be wrong to focus all of our prevention attention solely on this one cell. There are other issues we need to think about too, such as equipment. For example, if you are trying to prevent an automotive crash there are things that you can do about the car itself. You don't have to rely on changing the behavior of the person involved. For example, if you establish a better braking system in the car, that would be classified as a pre-event/equipment intervention.
There are also interventions that involve changes in the physical environment. Continuing with the car crash example, if we want to prevent car crashes we could do something about roadside hazards. We could remove trees from the edge of the road. Then, if someone has the misfortune of swerving off the roadway, this action isn't going to cause a fatal accident as a result of a collision with a large obstacle on the side of the road.
We can also change things about the social environment. For example, the legal environment could be changed. We could pass laws that would govern drinking and driving or that address other relevant issues.
In sum, the point of the Haddon Matrix is that each one of these cells represents an opportunity to think through prevention possibilities. In injury prevention planning, we should be careful not to devote all of our attention to one cell or two cells on the matrix.
The following case study involves a woman named Jackie Moore who lives in the western part of North Carolina. I've been privileged to have Jackie as a friend for about a decade. Jackie has been working in injury prevention for close to two decades now. She works for the Indian Health Service. What her work has done for injury prevention among the Native American population is really wonderful and startling. Through a lot of programs that she's imaginatively developed, she's been able to address the injury problem in a population that, unfortunately, has a very high rate of injuries. Reading [this case] should give you an appreciation of the work that Jackie's been able to do.
Case Study by Jackie Moore, MPH
I think what's remarkable about the work that Jackie and many of her colleagues in the Indian Health Service have done is that it addresses many different types of injuries. It's not focused only on one type of injury such as drowning or falls. Jackie's work focuses on several types of injuries in many different programs. She utilizes behavioral interventions and the legal system. She works on changing the social and physical environments such as high-risk sights of injuries. She has also shown interest in changing products so that they can be safer. It's a full range program that Jackie and others operate.
I think that what we've learned over the years is that this multifaceted approach is the most successful way to reduce injuries. Injury prevention shouldn't rely on just one type of intervention.
