Slide Presentation from the AHRQ 2007 Annual Conference

Two Filters to Enhance SNR

Graph showing risk increasing with impact and frequency.

Notes:

These two steps, or tools, to enhance the signal and diminish the noise are use of a risk matrix and barrier analysis. This is a process of simplification to "eliminate the unnecessary so that the necessary may speak" (Hans Hoffman, Abstract expressionist).

The Risk Assessment Matrix is derived from MIL-STD-882B. The matrix provides a systematic method for assigning a risk level to a failure event based on the severity of the danger and likelihood of the event's occurrence..

Hazard is a danger, whereas risk takes into account the danger and the likelihood.

Barrier analysis: Initial screen is based on matrix value (index) for the initiating event—assuming no recovery step occurred. This value, however, remains unchanged if the recovery step was an unplanned one.

Conditional on another variable?
Dependant on single human performance?
If computer supported, is it readily over-ridden?
Failure readily detected?
Planned or Unplanned?