Improving patient care: learning more from bad outcomes.

Many quality improvement efforts look in detail at episodes in which things have gone awry through error, to learn how to prevent repetition of that or related errors, with a particular focus on adverse drug reactions. Looking in a more global fashion at the various scenarios in which matters go amiss, rather than solely at the negative consequences of administering a therapy in error, allows us to derive more useful evidence about best therapeutic practice. An analytic strategy is presented to accomplish this aim, looking at the respective adverse effects associated with giving or with omitting a therapy, in each case both in situations in which the therapy is indicated and in situations in which it is contraindicated.