The “Preventable” in Preventable Medical Errors and the role of regulation

The term “medical errors” is often preceded by the modifier “preventable.” This essay considers the meaning of preventability, how it can be measured as well as the role of regulation in reducing the risk of preventable medical errors.

There are some medical errors for which preventability is rarely questioned. These include medical errors such as wrong site surgery (1), administering the wrong drug when the correct drug was ordered (2), or transplanting organs of the wrong blood type (3). Less preventable medical errors include judgment type errors such as case studies reported in journals, where one or more experts review the treatment decisions of a clinician and conclude that the clinician’s judgment was incorrect (4).

The role of FMEA

FMEA (Failure Mode Effects Analysis) is a tool that when performed adequately, can reduce the risk of preventable medical errors. Hospitals in the US that are accredited by JCAHO are required to perform at least one FMEA each year. The main output of FMEA is a series of mitigations, each of which is some process change implemented to reduce the risk of error. Because resources are limited, implementing all mitigations are not possible so the challenge is to find the set of mitigations that provides the highest reduction in risk for the least cost. Hence, preventability may be viewed in terms of the cost and effectiveness of a mitigation. A low cost and effective mitigation is associated with a highly preventable medical error, whereas a high cost and or less effective mitigation is associated with a less preventable medical error.

Preventability viewed in a decision analysis framework

Decision analysis, while beyond the scope of this essay is commonly to used to evaluate research opportunities in industry, whereby cumulative profit is graphed vs. cumulative R&D cost for a series of projects (5).

Figure 1 shows a similar type of graph for mitigations. Here, the cumulative cost of medical errors is graphed against the cumulative cost of mitigations. In decision analysis language, one conducts a “portfolio” analysis in that a “basket” of mitigations is selected (from a larger set of mitigations) that has the most effectiveness in reducing risk, for the least amount of cost.

Figure 1 – Portfolio type analysis for mitigations

The role of regulation

Regulation seems to be an inevitable response to adverse events that occur early on, as the public demands protection. The concept of regulation to prevent medical errors is simple. Through inspection, facilities are certified and / or accredited for the medical service that they provide. In theory, services that are likely to commit medical errors are denied accreditation, so the public is protected. The outcome of the inspection process can be viewed as a 2×2 table, similar to a medical test (Table 1).

Table 1 Inspection outcomes

Likely outcome Passes inspection Fails inspection
Commits medical errors Service allowed to harm public Public protected from medical errors
Doesn’t commit medical errors Service allowed to operate without harm Service unnecessarily shut down

This is somewhat of a conceptual table because if a service is shut down, one does not know whether medical errors will actually occur. But a key point is that hospitals rarely fail inspections such that accreditation is lost! (6) Hence, one can largely ignore the last column, which means among other things that accreditation is not useful as a means to test the capability of a service to prevent medical errors. One could of course suggest that more hospitals need to fail accreditation. However, the inspection process is an estimate of whether a hospital will commit errors and estimates have uncertainty. Even if the likelihood of medical errors were higher as judged by inspection, this must be traded off against the consequences of loss of accreditation, which could mean that many people loose their jobs and that some people will not have access to medical services, both of which can affect morbidity and mortality (e.g. must be traded off against the possibility of medical errors that also affect morbidity and mortality).

Although the inspection process is largely not a means to deny accreditation, it still may be viewed, at least conceptually, as a way to lower the preventable medical error rate. That is, during the inspection process, unsafe situations are documented to have been remedied, as no hospital wishes to loose accreditation. However, one may also question the effectiveness of a FMEA process that is conducted as part of a regulatory requirement.

FMEA goals and regulation

FMEA is now carried out as part of a JCAHO requirement; however, prior to 2002 it might have been performed as a hospital quality initiative unrelated to regulation. Consider the likely goals for each FMEA:

JCAHO FMEA Goal – Pass inspection Non regulatory FMEA Goal – Reduce risk of medical errors

Now a regulatory person might argue that the goal of reducing risk of medical errors is implied in the JCAHO FMEA goal of passing inspection. Whether this actually happens depends on how the inspection is carried out. In fact, there is evidence to suggest that inspections do not achieve this goal. For example, it was reported that the incidence of wrong site surgery is rising in spite of the fact that most hospitals pass (FMEA) inspections and remain accredited (7).

As a provider of FMEA software, feedback with potential clients revealed that many are seeking to “streamline” the way FMEA is performed since a hospital goal is not only to pass inspection but to do so with minimal effort. This is consistent with an analysis of quality initiatives in industry that have not been fruitful (8). This situation is not unique to FMEA. For example, most industries are required to obtain ISO 9001 certification (which is supposed to guarantee high quality) and once again, gaining and maintaining certification (with the least effort) is the main goal for industry. There is a consulting industry devoted to shepherding companies through the inspection process. Yet, analysis of the ISO 9001 process used by medical diagnostics companies to gain certification showed that there is no reason to believe that quality has been improved (9). Although some organizations may try to improve quality (and succeed), these activities are often largely separate from quality programs required by regulatory agencies.

One of the main problems with regulatory required quality programs is that there is too much emphasis on complying with “horizontal” standards. These standards provide broad guidelines without supplying details. While often favored by industry trade groups, such standards allow compliance to be achieved at the discretion of the user. In fact,  these are not really standards, since within the general guidelines, there is too much leeway – the main requirement is to provide documentation that whatever procedure was selected, was in fact carried out.

Some recommendations

There are no magic bullets. Ideally, a cultural change would affect attitudes toward quality programs, but that has not happened. Inspections and accreditation are here to stay and do fulfill a role. Within this framework, the following is recommended.

More emphasis on vertical standards – Vertical standards are needed, which proscribe how to do things. They should replace horizontal standards, which provide generic guidelines.

More measurements and reporting – Vertical standards should require an organization to set quantitative goals. Inspections should be less concerned with documentation that shows that a procedure was followed and more concerned with documentation that shows results vs. goals (e.g., what was measured and what was the goal).

Beware of some quality “gurus”

As a quality consultant, it may seem self-serving to complain about other organizations, but one should nevertheless be aware of some shortcomings. For example, the IHI (Institute of Healthcare Improvement) suggests use of before and after Risk Priority Numbers (RPN) to demonstrate risk reduction through FMEA (10). I and others have commented that detection should not be included in a priority ranking and that before and after rankings are also suspect since the highest severity, lowest probability event is often a common classification and whereas this event cannot have its ranking changed, it still may be beneficial to devote mitigation effort to these events (11-12). In fact , one could argue that recommendations such as the use of before and after RPNs adversely affects the culture needed for quality improvement.


  1. Scott D. Preventing medical mistakes RN 2000;63:60-64.
  2. An omnipresent risk of morphine-hydromorphone mix-ups. From the July 2004 Institute for Safe Medication Practices web site,
  3. Molter J. Background Information on Jesica Santillan Blood Type Mismatch Feb. 17, 2003 accessed 12/5, 2003 at
  4. Lukela M, DeGuzman D, Weinberger, S and Saint S. Unfashionably Late. New Eng J Med 2005;352:64-69.
  5. Assay Development and Evaluation: A Manufacturer’s Perspective. Jan S. Krouwer, AACC Press, Washington DC, 2002 pp 18-32.
  6. Managing risk in hospitals using integrated Fault Trees / FMECAs. Jan S. Krouwer, AACC Press, Washington DC, 2004 p 11.
  7. See:
  8. See
  9. Krouwer JS. ISO 9001 has had no effect on quality in the in-vitro medical diagnostics industry. Accred. Qual. Assur. 2004;9:39-43.
  10.  See
  11. Managing risk in hospitals using integrated Fault Trees / FMECAs. Jan S. Krouwer, AACC Press, Washington DC, 2004 pp 7-8 (Also see essay on detection).
  12. Schmidt MW. The Use and Misuse of FMEA in Risk Analysis. Available at

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