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Learning Objectives

After completing this chapter, the reader will be able to:

  • Define and compare the terms “medication errors,” “adverse drug events,” and “adverse drug reactions.”

  • Describe methods to identify medication errors and adverse drug events.

  • Assign an event type and severity to reported events.

  • Describe skill-based, rule-based, and knowledge-based errors.

  • Explain a systems approach to error.

  • Determine strategies health care practitioners and health systems can implement to reduce medication errors.

  • List two common methods of analyzing medication errors and adverse drug events that are utilized to develop action plans for error prevention and harm reduction.

  • Compare and contrast a Just Culture with a blame-free culture, and punitive culture.

  • Identify resources promoting best practices in patient and medication safety.


Key Concepts

  • image The terms “medication error,” “adverse drug event,” and “adverse drug reaction” are similar and often confused. They are interrelated, yet distinct occurrences.

  • image Several methods of identifying errors are recommended to gain a more global understanding of the risks and errors occurring within an organization.

  • image Classification of errors by type is a common method to identify common themes of medication events.

  • image Understanding the three modes of human performance (skill-based, rule-based, and knowledge-based) is important to understanding human errors.

  • image Humans will commit errors despite their best efforts not to. Therefore, it is critical to design systems that account for human error and put processes and technology in place to intercept errors before they reach and harm patients. The system should make it hard to do the wrong thing and easy to do the right thing.

  • image Poorly designed systems and processes are a significant contributor to error and subsequent patient harm. Errors rarely occur solely because of a mistake by a single health care professional, but rather in combination with one or more latent system failures.

  • image Incorporation of human factors (HF) principles into process design and product selection can improve safety.

  • image Failure modes and effects analysis (FMEA) is a prospective method of evaluating processes to identify how and why a process could fail, potential impacts of failure, and developing actions to prevent failure and mitigate harm.

  • image Evaluation of safety events through root cause analysis (RCA) and other methods is key to learning from errors and preventing reoccurrence.

  • image A Just Culture is a balance between accountability of organizations for the systems designed and the behaviors of employees within that system.


Much attention has been focused on adverse outcomes in health care in the past 20 years. While pockets of research in medical errors were developing prior to 2000, the National Academy of Medicine’s (NAM; previously named the Institute of Medicine [IOM] at the time) report, To Err is Human: Building a Safer Health System,1 released in late 1999, served as a catalyst for additional research in the causes and methods to prevent adverse outcomes in health care. Based on two landmark trials, this ...

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