The investigation of patient safety incidents

Before proceeding to explore the theme of the investigation of patient safety incidents, it is time to take stock of what we have explored so far of the topic. In the last few weeks we have reviewed the following:


The Surgical Assistant. Medical Heritage Library on Flickr.

The investigation of patient safety incidents is a process which, depending on how well it is carried out, has profound consequences on the patient, the involved healthcare professionals, and the organisation itself. The importance of the approach to investigating patient safety incidents was emphasised by Sidney Dekker in his book, The Field Guide to Understanding Human Error, where he distinguished between two mindsets to the handling of patient safety incidents: the old view or bad apple model which seeks to identify and sanction individuals, and the new view which sees error as the fallout of the complexity of systems in which people work.

CC BY 2.5, Link

Dekker strongly advocated the new view approach to investigating patient safety incidents, arguing that human error is a problem that begins in the world and not in the practitioner’s head. Therefore, rather than search for its causes, he advocated seeking to understand the local rationality principle behind the incident; this refers to the factors that made the error a reasonable act at the time to the people involved based on their goals, knowledge, and focus of attention. The new view, he added, emphasises the importance of ‘the perspective of the practitioner in the tunnel‘ because this is ‘critical to understanding‘ how the adverse event occurred. He explained that this understanding is important to prevent a recurrence of the incident because the same conditions that made sense to the practitioner, would make sense to others in similar circumstances in the future.

Whilst there are several techniques for investigating patient safety incidents, from confidential inquiry and critical incidence technique to significant event auditing and organisational accident causation model, root cause analysis (RCA) is the tool that is universally favoured. In its document titled Patient Safety Workshop: Learning From Error, the World Health Organisation defines RCA as ‘the systematic analysis of all the factors which predisposed to, or had the potential to prevent, an error’. Kieran Walsh has outlined several stages of root cause analysis of which five are directly related to establishing the cause or reasons for the incident:

      • Data gathering
      • Mapping the chronology or timeline of events
      • Identifying the contributory factors
      • Identifying the root causes
      • Developing recommendations
Data Protection and Privacy. Dominic Smith on Flickr.

Data-gathering is one of the most important stages of root cause analysis and Sidney Dekker also discussed this extensively. He explained that data gathering should focus on documenting four key factors that swayed those involved to make the error or errors that resulted in the incident. These are:

      • The critical junctions
      • The missed cues
      • The influences
      • The expectations

Establishing the timeline follows the data gathering stage, and Dekker advised that this should be created ‘around peoples communications and actions‘, and it should establish ‘what was said or done, when and how‘.

Secure Data. Blue Coat Photos on Flickr.

In arriving at their conclusions, Dekker cautioned against the influence of hindsight bias clouding the judgement of the incident investigators. Apart from its tendency to oversimplify the event, Dekker warned that hindsight bias may also influence the conclusions by introducing counterfactual language that sets a misleading standard of how things ‘should‘ have been done differently – a judgement that can only be made retrospectively. Hindsight bias, he added, enables patient safety investigators to ‘cherrypick‘ evidence which appear glaring only in hindsight, and may not have been so evident ‘at the time‘ the event was evolving.


The recommendations of the investigating team often focus on determining culpability of the practitioner in causing the incident. In his book Patient Safety, Charles Vincent referred to the incident decision tree developed by the National Patient Safety Agency (NSPA) which recommends four tests for determining culpability when investigating patient safety incidents, and these are:

      • The deliberate harm test: was there intent to harm
      • The incapacity test: was the practitioner influenced by ill health or substance abuse
      • The foresight test: did the practitioner depart from safe practice
      • The substitution test: would another person have acted in the same way,

In assessing culpability, mitigating factors must also be considered, and these include deficient training, experience, or supervision.

Magnifying glass on black book. Jernej Furman on Flickr.

In the next post, we will look at apology following patient safety incidents.

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