The anatomy of a near miss – 2/2005

February 13, 2005

A near miss implies that a catastrophic event (sentinel event in JCAHO terms) has nearly occurred. A “near miss” is actually a poor name – a “near hit” would be better. Alternatively, a “good catch” could be used since a catastrophic event has been prevented. However, near miss is universally understood and will be used here.

A near miss is shown as a cascade of events whereby a sentinel event has been prevented due to a detection and recovery sequence. In the figure below, if either detection or recovery fail, the sentinel event (the next event = event B in this cascade) occurs. Thus, detection and recovery play a key role in a near miss. The sentinel event is also the effect of the prior event.

Figure 1 Error event Cascade

One can further classify near miss events as follows:

Planned detection and recovery – Here, detection is a process step. Example. A lab specimen was examined for lipemia as required (planned detection) . Lipemia was found and the sample underwent an ultracentrifuge step (planned, successful recovery) before analysis.

Chance detection – Detection occurred only by chance. Example – A portable BP monitor was disconnected during an MRI. The BP monitor was then incorrectly reconnected to the IV line. A family member noticed the incorrect connection (chance detection) and called a nurse who corrected the problem (unplanned, successful recovery) (1).

Unsafe situation (Accident waiting to happen) – An error event is only recognized as such after a chance detection. Example – Two similar looking medications are next to each other. If an incorrect selection is made, the result could be fatal. Placing the similar medications next to each other can be considered to be a process error event. This error event may be a cause for selection of the incorrect medication. If the wrong medication is selected and this error is detected before administering the medication (chance detection and unplanned, successful recovery), a near miss has occurred.

One may further consider these cases with respect to FMEA and RCA (Root Cause Analysis).

Planned detection and recovery – FMEA analysis seeks to add planned detection and recovery where they were absent or to improve detection and recovery, by asking how can an error event be detected and what is the recovery.

Chance detection – During FMEA analysis, the addition of a detection step can be thought of as changing a chance detection to a planned detection. If an error event has occurred and been detected by chance, the addition of this detection as a planned process step would have been achieved through RCA.

Unsafe situation – An unsafe situation is an unrecognized error event. By definition if the error event is unrecognized, detection and recovery are unknown. By analyzing the process steps through FMEA, events that were previously unrecognized as potential errors could now be so recognized. Planned detection and recovery steps could then be added.

Chance detection implies an unsafe situation – If one considers the BP problem above, one could suggest that having a BP Luer connector that can attach to an IV line is an unsafe situation (e.g., an error). Starting with that premise there are several possible mitigations including training, warning labels, and different equipment which would prevent the incorrect connection.


  1. ISMP web site: