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Study links long hours with clinical errors

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In Brief

A new study documents what nurses already know: Nurses face a bigger risk of making clinical errors when they work overtime. Researchers found that the risks of making an error were “significantly increased” when nurses work:

  1. hifts lasting longer than 12 hours
  2. overtime
  3. more than 40 hours/week.

In the study, 393 hospital staff nurses kept a logbook of shifts they worked and errors they made (or nearly made) during a 2- or 4-week period. About 40% of the 5,317 work shifts that nurses logged exceeded 12 hours. Nurses reported making 199 errors and 213 near errors during their study period. More than half of the errors and near errors involved drug administration.

The likelihood of making an error was three times higher when nurses worked 12.5 hours or longer, compared with when they worked 8.5 hours or less. Working overtime also increased the odds of making an error, regardless of the length of the original shift.


Researchers say that, because more than 75% of scheduled 12-hour shifts last longer, shifts of shorter duration should replace 12-hour shifts. They conclude that the long and unpredictable hours documented in their study “suggest a link between poor working conditions and threats to patient safety.”


“The Working Hours of Hospital Staff Nurses and Patient Safety,” Health Affairs, A. Rogers, et al., July/August 2004. Illustrations by Michael Trinsey
    © 2004 Lippincott Williams & Wilkins, Inc.