Patient Safety Zone

Managing error

Error management approaches to detect, minimize, reduce or even prevent errors.





Systems Approach

We cannot change the human condition, but we can change the conditions under which humans work.

Reason J. (2000)

If we accept human fallibility, we need to rely on well-designed systems to support us in the workplace.  Unfortunately, current healthcare systems are often deficient in many ways. Awareness and better design of the three systems described previously will help to improve patient safety.

A few practical examples of system improvements:

  • Automate systems where possible and appropriate.
  • ‘Forcing functions’ should be added where appropriate. For example adding reminders and ‘double clicks’ to confirm doses, dosing intervals and durations of high-risk medications.
  • Standardise systems to reduce reliance on memory
  • Checklists are increasingly being used in Scottish hospitals, for example in pre-operative settings
  • Minimise staff interruptions and distractions.  One example of existing practice includes the wearing of a coloured ‘tunic’ by the nurse responsible for drug rounds
  • Reduce the number of steps and handoffs (transferring a task to another team member) in a given procedure or intervention
  • Add redundancies (‘double checks’) for high risk processes (examples include the need for two nurses to check intravenous medication)
Individual Approach

The individual’s awareness and recognition of ‘error traps’ can be improved.  Certain tools and techniques can help individuals to formally evaluate the error risks they may be faced with. There are a number of these tools available such as the ‘three buckets model’, which is described in the next tab.

Error management is most effective when a ‘systems’ and ‘individual’ approach is combined.

This article looks at error and adverse events in health practice:

Three Buckets Approach
image of a bucket with the word 'self' underneath
Image of a bucket with the word 'context' underneath
image of a bucket with the word 'task' underneath

Professor Reason proposed the ‘three buckets model’ to help health care professionals evaluate their error risk.  The amount of perceived risk in each ‘bucket’ is rated in turn by the health care worker as (1) low, (2) medium or (3) high.

The 'three buckets model'

  • Self: This bucket concerns the individual health care worker.  For example, is he or she fatigued and do they have the necessary experience and knowledge to deal with the demands at that time.
  • Context: This bucket represents all contextual factors, including environmental factors (distractions, interruptions, handovers), equipment failures, inadequate resources and time.
  • Task: This bucket contains all factors related to the task at hand and includes the task complexity, duration and physical demands.

Practical application of the ‘bucket model’

  • Each bucket may contain positive as well as negative factors. For example, the health care worker may be well-rested and in a supportive environment, but faced with a very complex task. 
  • The buckets are never completely empty.  Health care professionals are constantly performing tasks within a context.  There is always risk – only the level of risk changes.
  • The likelihood of error is represented by a combination of the entire contents of all the buckets.  However, full buckets do not always lead to error, just as nearly empty buckets are no guarantee of safety.  The amount of content in all of the buckets provides an estimation of the probability of error. 
  • As the probability of error increases, health care workers should acknowledge the risk, increase vigilance and consider additional defences (barriers).


Think of a recent clinical situation where you had concerns or a ‘near miss’.

  • Apply the three buckets model to that situation and try to evaluate your level of risk.
  • What could you have done to reduce the risk?
  • How can you apply this technique as part of your everyday practice?