Each day, when you take your morning shower, you face a 1 in 1,000 chance of serious injury or even death from a fall. You might at first think that each time you get into the shower your chance of a fall and serious injury is 1 in 1,000 and therefore there is very little to worry about. That is probably because you remember that someone once taught you the famous coin-flip rule of elementary statistics: because each toss is an independent event, you have a 50% chance of heads each time you flip. But in this case you would be wrong. The actual chance of falling in the shower is additive. This is known in statistics as the “law of large numbers.” If you do something enough times, even a rare event will occur. Hence, if you take 1,000 showers you are almost assured of a serious injury—about once every 3 years for a person who takes a shower every day. Of course, serious falls are less common than that because of a variety of intervening factors. Nevertheless, according to the CDC, mishaps near the bathtub, shower, toilet, and sink caused an estimated 234,094 nonfatal injuries in the United States in 2008 among people at least 15 years old. In 2009, there were 10.8 million traffic accidents and 35,900 deaths due to road fatalities in the United States. The CDC estimates a 1-in-100 lifetime chance of dying in a traffic accident and a 1-in-5 lifetime chance of dying from heart disease. But none of these realities affect our behaviors very much. We don’t take very many (if any) precautions when we shower. We text, eat, talk on the phone, and zone out while driving, paying little attention to the very real risk we pose to ourselves (and others) each time we get in the car. And we keep eating at McDonald’s and smoking cigarettes, completely disregarding the fact that these behaviors could eventually affect our health in extreme and fatal ways. On the other hand, there is zero proven risk of death as a result of the diphtheria- tetanus- pertussis (DTP) vaccine.
Emergency Department Visits for Injury in School-aged Children in the United States: A Comparison of Nonfatal Injuries Occurring Within and outside of the School Environment