When you are very sick, you go to the hospital to get better. But what if the hospital you choose actually makes you sicker, or even kills you?
"The worst thing is to go to a hospital to not die from one thing, and then to end up dying from something else," said Dubner.
Actress Alicia Cole never thought she would almost die from a hospital-acquired infection three years ago.
"I was just living my dreams," Cole, 47, said. "I had two national Budweiser commercials running. I was representing the state of California against childhood obesity. Everything was good."
But Cole's life changed when a routine gynecological procedure at a Los Angeles area hospital went terribly wrong.
"The next day after surgery, I was very nauseous and I had a fever," Cole said. Soon, it became clear that Cole had contracted a necrotizing fasciitis, or "flesh-eating disease" -- one of over 1.7 million hospital-acquired infections that are contracted annually in the United States.
"My stomach just rotted, right before my eyes. It looked like black tar, or burned rubber. I was swelling. It was horrible," Cole said. Even worse, she said, "What happened to me in the hospital was absolutely preventable."
Coles attributes her infection to the carelessness of health care personnel, who she says failed to observe basic sanitary standards during her surgery and post-operative care.
Cases like Cole's could be prevented through what seem like common-sense strategies, such as hand washing -- but old habits die hard, explain Levitt and Dubner.
"Studies have shown that hospital personnel wash or disinfect their hands fewer than half the times they should," Levitt and Dubner write. "And doctors are the worst offenders, more lax than either nurses or aides." In fact, one Australian study reported a hand washing compliance rate of only 9 percent.
Why would doctors, who are supposed to cure diseases, not cause them, be so careless about hand washing?
The connection between dirty hands and deadly infections has been known for over 150 years, since Austrian doctor Ignatz Semmelweis insisted that colleagues wash their hands before delivering babies, drastically cutting deaths among new mothers.
But the reasons for low rates of hand washing compliance among doctors are complex. Dr. Craig Feied, an expert in emergency medicine who has treated over 80,000 patients, estimates that sometimes he would interact with more than 100 patients per shift.
"If you look at a busy nurse, who might touch 100 or 200 patients during a shift, going back and forth from room to room and area to area, the number of times they would have to wash their hands can add up to half the shift time or more," said Feied.
"We're so distracted, whether you're a physician in the hospital or a nurse. You have so many competing interests, to get your work done, that it's very easy to forget that you didn't stop after the patient and wash your hands," said physician Paul Silka, of Cedars-Sinai Medical Center in Los Angeles.