ABSTRACT
This chapter maps what is known about the scope and scale of adverse events. Several terms are used to describe the things that go wrong in health care. Medical errors have always occurred, and cannot be totally eliminated, but realization of the magnitude of adverse events in modern medicine has alarmed policy makers and the public. Runciman and colleagues discusses the forms of error that underlie the many things that go wrong in the delivery of health care. The two perspectives on causation, people failure and system failure, are encapsulated in the titles of these reports: To Err Is Human, and An Organization with a Memory. Medical error is not a new phenomenon, and while there is no reason to believe that contemporary health professionals make more mistakes, there are more opportunities for things to go wrong. In other words, healthcare has become riskier.
