Stopping Rules for Root Cause Identification
A common problem that Root Cause Analysis teams face when performing a root cause analysis is deciding when to stop pursuing deeper for root causes. The team should work on identifying deeper root causes, because when deeper, underlying causes are identified and addressed, more fundamental, broadly applicable solutions can be developed and implemented.
Stopping Rules for Root Cause Identification
As shown in Figure 1, an increased depth of analysis leads to an increased level of learning about the organization and corrective actions that apply across a greater portion of the organization.
Figure 1. Task Triangle
But when does it make sense to stop? This paper outlines six stopping criteria.
1. Pursuing the causes deeper does not result in practical action items.
Although the analysis could delve deeper into the underlying causes of the problem, identification of these underlying causes would not result in practical action items. During an analysis issues are sometimes encountered that are outside the control of or sphere of influence of the group that commissioned (requested) the investigation. At this point, identification of deeper causes, typically does not results in practical action items.
For example, shortly after installation, a motor bearing failed. The bearing had been installed incorrectly by factory personnel. Identifying root causes related to the installation processes used at the factory will probably not be effective because you have little or no control over the processes used at the factory. The team should, however, consider (1) changes to receipt inspection practices and (2) switching suppliers (two actions that under the control of the organization).
As another example, if the investigation was commissioned by the operations manager, identification of root causes outside the control of the operations manager may not yield practical corrective actions if the plant manager does not support the investigation.
As a third example, the investigation team identifies that a design error that occurred about 10 years earlier contributed to the failure. Even if the data were available to identify what went wrong 10 years earlier, it may be difficult to develop recommendations that are applicable to current design practices.
2. The root cause identified meets the organizations definition of a root cause.
ABS Consulting’s SOURCE™ technique requires organizations to identify the standard, policy, or administrative control (SPAC) issue that is the underlying cause of a problem in order to complete the root cause identification process. The process does not require the cause of the SPAC problem to be identified.
For example, an operator failed to notice a high reactor temperature because there was no high temperature alarm. The RCA team identified the intermediate causes as the lack of an alarm, caused by a design issue. This is turn was caused by failure of the designer to consult with the operations staff (which would have identified the need for a high temperature alarm). The designer did not consult with the operations group because there was no policy in place that required this action. This depth of analysis meets the requirements of using the ABS Consulting Root Cause Map™ by identifying a standard, policy or administrative control issue (lack of a requirement in the SPAC) that eventually lead to the problem. If the team develops recommendations to address each of the causes identified in the chain above, effective corrective and preventive actions should be implemented.
The RCA team will then have to decide whether digging deeper is appropriate. They could decide to answer the question: “Why was there was no requirement in the SPAC for the designer to consult with the operations group?” However, there may be very limited data available to answer this question. As a result, developing an effective strategy for preventing the problem in the future will be difficult.
3. The organization’s resources are more effectively allocated to other causes of the incident.
If the team sees that its resources are more appropriately utilized in other areas, the team may choose not to pursue root cause identification any further. This assumes the team has identified root causes in other areas for which practical action items have been developed.
For example, the RCA team is trying to eliminate problems associated with restoring equipment to service following maintenance. One approach is to prevent the errors from occurring to begin with. Another approach is to improve the detection and correction processes associated with these errors. The RCA team attempted to find ways to reduce the potential for these errors, but nothing looked promising. The team did find two or three promising approaches for improved detection and correction of the errors. Therefore, the team did not pursue prevention of the errors and further because the detection and correction strategies reduced the risk sufficiently.
4. The organization chooses not to pursue the causes any further.
This situation can occur because a variety of factors can influence the performance of a root cause analysis. Some of these factors may not be related to the scope of the investigation team’s charter. Consideration of these factors will be driven by the individual or group commissioning the analysis.
For example, a maintenance technician fell down a couple stairs and injured his ankle. The RCA team reviewed the situation and found the stairs were in good repair, the technician was not carrying anything in his hands, was wearing appropriate footwear, the steps were dry, the lighting was adequate, and the technician appeared fit-for-duty. The team could not identify any actions it wanted to take to modify the situation. As a result, the team decided not to pursue root causes any further. On ABS Consulting’s Root Cause Map, this decision is coded as tolerable risk (Node 5).
As another example, a fan failed as a result of a drive belt failure. The company looked at supplier issues as potential root causes. However, the company decided not to pursue root causes associated with supplier qualification processes any further and instead, focused its efforts in other areas.
5. There is insufficient data to pursue further analysis of the causes.
In some cases, there is insufficient data available to determine the root causes of the problem. In this situation, recommendations are generally developed to enhance the data collection processes so that sufficient data will be available to determine the underlying causes when the next failure occurs. So, if these recommendations are implemented, future root cause analysis teams should have the information available to further pursue underlying causes.
For example, the team is investigating the failure of a pump. It has gathered all of the available data from interviews and examined the failed parts. However, the cause of the failure cannot be determined. The team needs vibration analysis data and computer records in order to determine the causes of the pump failure. However, the historical data are not available because the computer was not set up to save the historical data. As a result, the team could not pursue the analysis further. They developed recommendations to store additional computer data for this and other pumps.
6. The underlying causes are related to criminal activity, sabotage, or other matters best dealt with by the human resources organization.
These types of causes are generally not dealt with by root cause analysis teams. Most RCA programs try to shield themselves from activities which result in overt punishment of personnel. The reason is that most programs rely upon the participation of employees on investigation teams and through interviews to perform the majority of the analysis. As a result, if the RCA program is associated with punishment of employees engaged in criminal activity, sabotage, or other similar matters, personnel tend not to cooperate with the RCA teams. In the investigation report, the team must be very sensitive to any implication that they were involved in punishment of personnel.
Even in situations where criminal activity, sabotage or other similar matters are encountered during an analysis, the team should pursue issues related to improved detection and correction of those activities.
a. For example, if an individual failed to perform a task correctly because they were drunk, human resources should deal with the consequences associated with the individual violating the company rule concerning alcohol. However, the RCA team should review the adequacy of policies and procedures the organization has to detect individuals that are not fit for duty.
As a general rule, root cause analysis teams should continue pursuing deeper underlying causes. However, at some point, the team must stop. Using these guidelines will assist root cause analysis teams in focusing their efforts on activities that are most likely to result in effective risk reduction efforts.
Lee N. Vanden Heuvel
Manager – Incident Response and Root Cause Analysis Services
LNV@absconsulting.com
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The 3rd edition of the Root Cause Analysis Handbook: A Guide to Efficient and Effective Incident Investigation is now available.
By ABS Consulting – Lee N. Vanden Heuvel, Donald K. Lorenzo, Randal L. Montgomery, Walter E. Hanson, and James R. Rooney
Includes:
- A 17 inch by 22 inch pull-out Root Cause Map
- CD-ROM
- Dedicated Web Resources (registration required)!
See www.rothstein.com/new/nr388.htm
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