Failure Mode and Effects Analysis
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Roberts L, Johnson C, Shanmugam R, et al. Computer simulation and six-sigma tools applied to process improvement in an emergency department. 17th Annual Society for Health Systems Management Engineering Forum; 2005; Dallas, TX; 2005.
Latino RJ. Case studies. Patient Safety: Patient safety: the PROACT root cause analysis approach. Boca Raton, FL: CRC Press; 2009. p. 171-87.
Failure mode and effects analysis (FMEA) is a method that attempts to identify all possible failures that can occur within a system and then determines what the effects of those errors would be.
When planning improvements to existing processes, products, or services.
For error forecasting.
For mistake prevention.
When using a pre-existing process, product, or service in a new manner.
For periodic evaluation of existing processes, products, or services.
When examining failures.
1. ASSEMBLE A CROSS-FUNCTIONAL TEAM. The team should be comprised of individuals who are knowledgeable about the concept being analyzed.
2. IDENTIFY THE SCOPE of the FMEA. Parameters such as the boundaries, level of detail, and whether a concept, system, or process is being analyzed will all drive the scope. Flowcharts will allow you to determine the scope and ensure all team members understand it.
3. IDENTIFY THE FUNCTIONS OF YOUR SCOPE. Determine what the purpose of the element you are analyzing is. Name it in verb and noun format. After this the scope will be dissected into separate compartments, subsystems, items, and so forth and the function of each of these will be identified.
4. For each function, IDENTIFY ALL THE WAYS FAILURE COULD OCCUR - i.e. the potential failure modes. If the failure modes do not show a loss of a particular function, it may be necessary to rewrite the function to include additional detail.
5. For each failure mode, IDENTIFY ALL THE CONSEQUENCES - the potential effects of failure, on the element being analyzed. Determine what the patient would experience if the failure occurs.
6. EVALUATE THE SEVERITY OF EACH EFFECT(also termed the severity rating, or S). This is typically done on a scale from 1 to 10, where 1 in insignificant and 10 is catastrophic. If there are multiple effects for a failure mode, record the effect with the highest severity rating on the FMEA table.
7. DETERMINE ALL POTENTIAL ROOT CAUSES for each failure mode. Record all the causes for each failure mode.
8. DETERMINE THE OCCURRENCE RATING (or O) for each root cause that was identified in the previous step. This is an estimate of the likelihood the failure will occur, and is rated on a scale from 1 to 10, with 1 being extremely unlikely and 10 being inevitable. List the occurrence rating for each cause on the FMEA table.
9. IDENTIFY THE CURRENT PROCESS CONTROLS for each cause. These are controls in place to prevent failures from getting to the patient. They could prevent the cause completely, reduce its probability of occurring, or detect the problem after it has occurred but prior to the patient being affected.
10. DETERMINE THE DETECTION RATING (or D) for each control. This is an estimate of how well your controls can detect a cause or failure mode prior to the patient being affected. This is rated on a scale from 1 to 10, with 1 indicating that detection is absolutely certain and 10 indicating the problem will definitely not be detected or there is no control in place. Record the detection rating for each cause.
11. (Optional for most industries) IS THIS FAILURE MODE ASSOCIATED WITH A CRITICAL CHARACTERISTIC? If yes, then record a Y or N in a column labeled "Classification" to denote whether you need special controls. Typically, critical characteristics will have a severity rating of 9 or 10 and occurrence and detection ratings greater than 3.
12. CALCULATE THE RISK PRIORITY NUMBER (RPN). The RPN is equal to the product of the S (severity rating), O (occurrence rating), and D (detection rating) values (so RPN = S x O x D). Calculate criticality by multiplying the S and O values (criticality = S x O). These values will aid you when ranking the order to address potential failures.
13. IDENTIFY RECOMMENDED ACTIONS, whether they are changes that diminish severity or occurrence, or are extra controls that improve error detection. Make note of the individuals responsible for these actions and create completion deadlines.
14. NOTE RESULTS and the date the actions from the previous step are completed on the FMEA form. If the actions change any S, O, or D scores, adjust them accordingly and calculate new RPNs.
Word processing or spreadsheet programs can be used for the analysis and maintain simplicity while providing an easy means of recording data.
Can prepare for and remove possible error causes.
Provides a rating for the three most significant aspects of a failure mode.
Not easy to do, and tends to take time.
The method is not foolproof when evaluating the highest risk and priority for an action.
American Society for Quality. Process analysis tools: failure modes and effects analysis (FMEA). 2009 [cited 2009 July 22]; Available from: http://www.asq.org/learn-about-quality/process-analysis-tools/overview/fmea.html
Lighter D. Process orientation in health care quality. In: Moore C, editor. Quality management in health care: principles and methods. 2nd ed. Sudbury, MA: Jones and Bartlett Publishers; 2004. p. 43-101.
George M, Rowlands D, Price M, et al. Selecting and testing solutions. The lean six sigma pocket toolbook. New York: McGraw - Hill; 2005. p. 253-76.