Intended for healthcare professionals


Not again!

BMJ 2001; 322 doi: (Published 03 February 2001) Cite this as: BMJ 2001;322:247

Preventing errors lies in redesign—not exhortation

  1. Donald M Berwick, president and chief executive officer (dberwick{at}
  1. Institute for Healthcare Improvement, 375 Longwood Avenue, Boston, MA 02215, USA

    Again, a young patient with leukaemia is dying, not from his disease, but from an erroneous intrathecal injection of vincristine, intended for intravenous use.1 Again, the newspapers express outrage; they count up to 13 identical cases over the past 15 years. The hospital apologises, again, and two doctors are suspended, pending “investigation.” The NHS explains; steps will be taken, again.

    And trust erodes, again, as a confused public, grieving with the patient and his family, wonder if they are safe. Spurred by the headlines, each asks, again, “Could I be next?” The answer, of course, is, “Yes.”

    Less than a year ago the chief medical officer of England's NHS, in a landmark report on threats to patient safety in the NHS, courageously labelled the problem of medical errors as pervasive and consequential. He promised progress and even specified this very error—intrathecal injection of intravenous chemotherapeutic agents—as one targeted for “zero” occurrences: not just safer, but perfectly safe.2 So how could this happen—again?

    The answer is surprisingly mundane. It is this: we are human, and humans err.3 Despite outrage, despite grief, despite experience, despite our best efforts, despite our deepest wishes, we are born fallible and will remain so.

    There are two video rental stores in my town—Blockbuster and West Coast Video. I rented Pleasantville from Blockbuster and returned it to West Coast Video the next night. I usually do not make that mistake, but sometimes I do. When it involves videos, it is inconvenient; when it involves vincristine, it is lethal. But, it is the same mistake. Among the many errors human beings make—infrequently, but inevitably—is confusing similar tasks. We always have, and we always will. And, that is only one of the errors that human beings make—inevitably.

    Being careful helps, but it brings us nowhere near perfection. When the stakes are high—vincristine instead of videos—we attend more to the details and check each other out. That reduces the error rate, which is why only 13 patients have died from intrathecal vincristine, not 1300. But just “trying harder” makes no one superhuman. Exhortation does not help much, nor will suspending the doctors, nor will outrage in the headlines, nor even will guilt.4 Suspend every doctor today who makes an error today, and the error rates in the NHS tomorrow will be exactly the same as today's. There is no remedy to be found in selecting heroes, nor in seeking Superman. Tomorrow, like today, we will be human.

    The remedy is in changing systems of work. The remedy is in design. 3 5 A small number of children used to be killed each year by their parents' inadvertently backing their cars over them as they switched to reverse gear. The car would suddenly jump back and strike the child. That almost never happens today because almost all cars with automatic transmissions have a lockout feature: they cannot be switched into reverse gear unless the driver's foot depresses the brake pedal. A small number of patients used to die each year in operating theatres because the anaesthetist inadvertently connected the nitrous oxide tank to the oxygen line and vice versa. That almost never happens now, because the connecting fittings for oxygen and nitrous oxide have been made different from—and incompatible with—each other on all anaesthesia machines. Not even a saboteur today, much less a fatigued doctor, could connect the oxygen line to the nitrous oxide: it cannot be done.

    Equipment is not the only possible object for productive redesign. We can, using modern principles from human factors engineering, reliability sciences, research on group dynamics, communication theory, and semiotics (to name but a few relevant disciplines), devise better job and task designs, better alarms and signalling systems, better communication patterns, better team training, and better simulation environments for skill building.6 All these can help bring us to the safe system that we really want in health care, and all accept human error as inevitable—and design around that fact. The human factors community has a wonderful saying, “Honour thy user.”

    I do not know what specific design change will make this case of intrathecal vincristine the very last one. It probably has something to do with the foolproofing approach that now keeps oxygen and nitrous oxide separate in surgery. Why should it be possible to connect an intravenous line to an intrathecal catheter? But, I do know that expecting perfection in human action, or simply telling our doctors and nurses to “try harder”—not to kill their patients by mistake—has nothing at all to do with our eventual success.

    The goal should be extreme safety. I believe we should be as safe in our hospitals as we are in our homes. But we cannot reach that goal through exhortation, censure, outrage, and shame. We can reach it only by commitment to change, so that normal, human errors can be made irrelevant to outcome, continually found, and skilfully mitigated. So long as it involves humans—and thank God it does—health care will never be free of errors. But it can be free of injury.


    • Embedded Image

      The BMJ devoted a theme issue and a conference last year to reducing medical errors and promoting patient safety. To read this issue, and for further information on the ideas advanced in this editorial, please see


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