Death by airbag

The US National Highway Traffic Safety Administration (NHTSA) estimates that airbags installed in automobiles have saved some 10,000 lives as of January 2004. A just-released study by a statistician at the

, however, casts doubt on that assertion.

In fact, said UGA statistics professor Mary C. Meyer, a new analysis of existing data indicates that, controlling for other factors, airbags are actually associated with slightly increased probability of death in accidents.

"NHTSA recorded 238 deaths due to airbags between 1990 and 2002, according to information about these deaths on their Web site," said Meyer. "They all occurred at very low speeds, with injuries that could not have been caused by anything else. But is it reasonable to conclude that airbags cause death only at very low speeds? It seems more likely that they also cause deaths at high speeds, but these are attributed to the crash."

"For any given crash at high speed, we can't know what would have happened if there had been no airbag; however, statistical models allow us to look at patterns in the data, and compare risks in populations, in a variety of situations."