Applying Root Cause Analysis

In the following sections, a number of methodologies for accident analysis will be presented. These focus primarily on the sequence and structure of an accident and the external causal factors involved. These methods provide valuable information for the interpretation process and the development of remedial measures. Because most of these techniques include a procedure for delineating the structure of an incident, and are therefore likely to be time consuming, they will usually be applied in the root cause analysis of incidents with severe consequences. 

In the second case study, variation tree analysis and the events and causal factors chart/root cause analysis method are applied to an incident in a resin plant. This case study illustrates the application of retrospective analysis methods to identify the imderlying causes of an incident and to prescribe remedial actions. This approach is one of the recommended strategies in the overall error management framework described in Chapter 8. 

The case study has documented the investigation and root cause analysis process applied to the hydrocarbon explosion that initiated the Piper Alpha incident. The case study serves to illustrate the use of the STEP technique, which provides a clear graphical representation of the agents and events involved in the incident process. The case study also demonstrates the identification of the critical events in the sequence which significantly influenced the outcome of the incident. Finally the root causes of these critical events were determined. This allows the analyst to evaluate why they occurred and indicated areas to be addressed in developing effechve error reduchon strategies. 

Although there are differences between various predefined trees, the basic method to perform a root cause analysis using the trees is similar whichever tree is used. The following basic steps apply ... 

Once the facts have been established and an understanding of the event has been established, a root cause analysis can be carried out in order to apply lessons learned to a broader set of circumstances. There are four types of root cause analysis ... 

Standard root cause analysis should be applied where possible. It is relatively simple, effective and compatible with linear hierarchical structure of internal management. Its applicability ends at the boimdary of internal safety management. 

When we look at the factors that are identified in the interviews, we can see that the different factors, and hence, the related explicit uncertainty that is caused by them, can all be related to the different stages of the product lifecycle as, for example, defined by Bedford, Quigley and Walls (Bedford et al. 2006), i.e. concept and definition, design and development, manufacturing and installation, operation and maintenance. We see for example that the concept root-cause analysis (here, uncertainty is caused by this concept because we do not know the extent to which we are able to find the root-cause) can typically be related to the operation and maintenance phase. On the other hand, the concept supplier management (here, uncertainty is caused by the unknown level of quahty with which supplier management is applied) typically relates to the design and development phase. 

For Statistical Forecast, it is important to define a process to formally analyze and cluster the SKUs sold in different customers and channels based on sales volume and demand variability, in order to apply an approach that combines statistical forecast for SKUs with low variability and actual POS demand information for SKUs with high variability. It is also suggested to implement a root cause analysis to map and understand the reasons of low forecast accuracy by SKU, and then, implement an effective action plan to fix the problems. 

The Causal Factors Chart is a formal, and systematic, incident investigation and root cause analysis technique. The technique depicts the events and conditions leading up to an incident. It combines critical thinking, logical analysis, and graphic representations to analyze and depict an incident event scenario. It helps strncture the analysis and data gathering processes to ensure necessary and snfficient information is collected. The CFC also has been applied to Root Cause Analysis. The CFC is sometimes referred to as the Events and Causal Factors (ECF) chart. The ECF chart depicts the necessary and sufficient events and causal factors associated with a specific incident scenario. 

Implementing effective corrective actions for each cause reduces the probability that a problem will recur and improves reliability and safety. Root cause analysis enables improvement of reliability and safety by selecting and implementing effective corrective actions. First, identify the corrective action for each cause, and then apply the following criteria to the corrective actions to ensure they are viable. If the corrective actions are not viable, reevaluate the solutions. 

In use, some unanticipated misbehaviour of interfacing applications has been observed, and following a safety root cause analysis, the need to apply improved development methods was recognised and promulgated. 

Finally, an additional way to mitigate shipping failures is to use shock indicators in the shipped product. A typical shock indicator changes color if the applied G values exceed a preset threshold. The use of a shock indicator in products can help in root cause analysis of failed parts. 

Root cause analysis (RCA) of adverse surgical outcomes is used in high-lia-bility industries, but still not widely applied to analyze and resolve and improve adverse medical outcomes. Conventional RCA works linearly and backwards to identify root causes with limitations by the traditionally deterministic thinking, creating bias. In contrast, simulation RCA places the investigation in the context... 

Root cause analysis is attractive because it promises to provide a simple but definitive answer to a problem. It thus satisfies what Friedrich Nietzsche called a fundamental instinct to get rid of (these) painful circumstances. It is therefore hardly surprising that this set of methods is widely applied in many industries, for instance in health care. Indeed, the first response to a major... 

If your Trust offers Root Cause Analysis training, undertake it and apply the learning to minor incidents you spot in everyday practice. Remember, one day you may be the Si s investigating consultant, so this is all useful practice. 

Let us consider one type of root cause analysis before leaving the topic of root cause analysis completely. Most workplaces are dynamic and subject to change. Thus, the use of change analysis is often an appropriate root cause analysis to apply. 

Root Cause Analysis—Processes are provided to identify, analyze, document, conununicate and mitigate or eliminate root causes of performance problems and operational incidents. Industry-recognized RCA techniques should be applied when investigating and identifying lessons learned from incidents, near misses, and performance concerns. Investigation recommendations should be tracked until resolution. 

The report presents the findings from the analysis of the RCP failures. Estimates of the annual frequency for the spectrum of leak rates induced by RCP seal failures and their impact on plant safety (contribution to coremelt frequency) are made. The safety impact of smaller RCP seal leaks was assessed qualitatively, whereas for leaks above the normal makeup capacity, formal PRA methodologies were applied. Also included are the life distribution of RCP seals and the conditional leak rate distributions, given a RCP seal failure the contribution of various root causes and estimates for the dependency factors and the failure intensity for the different combinations of pump designers and plant vendors. 

To be effective the investigation must apply an approach which is based on basic incident causation theories and use tested data analysis techniques. Investigating incidents to determine root causes and make recommendations can be as much an art as a science. Within the industry, best practices in incident investigation have evolved substantially in the last 20 years. This chapter provides a brief overview of some of the more relevant causation theories. 

Progressive companies use a more structured and comprehensive team approach to identify root causes. Scientific principles and concepts are applied to determine root causes and make recommendations to prevent recurrence. Effective investigations should use tested data analysis tools and methodologies to seek the identification of multiple causes. To be repeatable, the investigation should use a systematic approach, which may also be prescriptive. As a rule, the benefits of this systematic approach result from two actions ... 

Checklists may also be used to supplement other tools for example, checklists on human factors may be used in conjunction with logic trees. Similarly, checklists may be used in combination with structured brainstorming tools such as What If/Checklist and Hazard and Operability (HAZOP) Analysis.(P It is also a good practice to apply a tool like the 5-Whys to the root causes identified from the checklist to verify whether they are truly root causes. 

Causal factor identification is relatively easy to learn and apply to simple incidents. For more complex incidents with complicated timelines, one or more causal factors can easily be overlooked, however, which inevitably will result in failure to identify their root causes. There are a number of tools, such as Barrier Analysis, Change Analysis, and Fault Tree Analysis, that can assist with bridging gaps in data and the identification of causal factors. Each of these tools has merits that can assist the investigator in understanding what happened and how it happened. 

Whenever a proactive maintenance strategy is applied, three steps are necessary to ensure that its benefits are achieved. Since proactive maintenance, by definition, involves continuous monitoring and controlling of machine failure root causes, the first step is simply to set a target, or a standard, associated with each root cause. In oil analysis, the most important root causes relate to fluid contamination (particles, moisture, heat, coolant, etc.). 

Failure analysis is another key role of the lab to study warranty returns and identify root causes of problems. There are many new industry and customer-specific test methods that must be applied. Many lab managers indicate they never do the same test twice in a month, but have to adapt to changing needs. Software plays a big role in the ability of the lab to quickly change over test methods and data analysis. These... 

Chronic failures, which are very frequent events, and that when they are eliminated or the root causes controlled, restored functionality is achieved to its peak and the expected work level rises. These failures are difficult to control or eradicate, and this is only achieved by applying failure analysis, and they are often accepted as a normal part of the production... 

---