Causal factor identification

Causal factor identification tools are relatively easy to learn and easy to apply to simple incidents. For more complex incidents with complicated timelines, one or more causal factors can be overlooked, ultimately leading to missed root causes. Another disadvantage is that an inexperienced investigator could potentially assume that suppositions are causal factors, when in reality the supposed event or condition did not occur. 

The process of evidence gathering, timeline development, scenario determination, and causal factor identification is somewhat iterative, and therefore some of the tools and quality tests previously described may assist in causal factor identification. More specifically, barrier analysis and change analysis, together with a completeness test, can ensure that all valid causal factors are identified. 

First, it is necessary to identify the multiple causal factors of the incident. The procedures in Causal Factor Identification may be used to identify tbe causal factors from a timeline or sequence diagram (including a causal factor chart). 

Setting the above knowledge and proposals together leads to integrated incident investigation procedure which is stUl based on the timeline development, causal factor identification and causal factor chart development, but which allows the determination of different Incident Cause Level for each of multiple causes. If the Incident Cause Level of specific cause is outside the internal safety management, the apph-cation of non-hnear analysis method is recommended. 

Causal Factors Identification of Factors Possible Corrective Actions... 

Promote root causal factor identification, analysis and resolution systems. 

A review of the forementioned documents will provide an inexpensive and valuable education. Now, to extend the resource list, five books on incident investigation and root causal factor identification and analysis and one Manual are referenced. There are other resources. 

Training Agenda Data collection Causal factor determination Root cause identification Writing... 

In general, the companies surveyed use one of two main methodologies to determine root causes. The first involves timeline construction followed by logic tree development. The second involves timeline construction, identification of causal factors, followed by the use of predefined trees or checklists. These two approaches are discussed in detail in Chapter 9. 

Timeline construction, identification of causal factors, and predefined trees or checklists. 

Once the evidence has heen collected, a timeline or sequence diagram developed, and the actual scenario confirmed, the investigation can proceed to the next stage, the identification of causal factors. These causal factors are the negative events and actions that made a major contrihution to the incident. 

The following tools can assist with the identification of causal factors for complex incidents with complicated timelines. 

The design of most process plants relies on redundant safety features or layers of protection, such that multiple layers must fail before a serious incident occurs. Barrier analysis ) (also called Hazard-Barrier-Target Analysis, HBTA) can assist the identification of causal factors by identifying which safety feature(s) failed to function as desired and allowed the sequence of events to occur. These safety features or barriers are anything that is used to protect a system or person from a hazard including both physical and administrative layers of protection. The concepts of the hazard-barrier-target theory of incident causation are encompassed in this tool. (See Chapter 3.)... 

Change analysis o) (also known as Change Evaluation/Analysis, CE/A) is another tool that can assist the identification of causal factors. It is useful for brainstorming about what has changed since conditions were safe, or perceived as safe. It may also be used for hypothesizing potential contributory factors to a hazardous condition or action. 

The identification of causal factors points us to the key areas that need to he examined further for why that factor existed. It acts as a filter to limit the number of areas that are subjected to further analysis to determine root causes. This critical activity must be performed diligently and systematically to identify every causal factor applicable to the specific incident. If a causal factor is missed, one or more root causes will likely be omitted as well, which could lead to similar incidents in the future. 

Using the augmented control structure, the remaining activities in STPA are to identify potentially hazardous control actions by each of the system components that could violate the safety constraints, determine the causal factors that could lead to these hazardous control actions, and prevent or control them in the system design. The process thus involves a top-down identification of scenarios in which the safety... 

If hazard identification and analysis do not relate to actual causal factors, corrective actions will be misdirected and ineffective. 

When 1 provided counsel to clients in the early stages of development of computer-based incident analysis systems, insurance claims reports and supervisors investigation reports were examined as possible sources of data. Having found those sources to be inadequate as respects causal factors, and not having found other reliable sources, I advised clients not to include causal data in their computer-based analytical systems. For analytical purposes, such systems were reasonably accurate for injury and illness types, for parts of body injured, and for identification data such as location, time of occurrence, department, and so on. 

But, there has been a significant and appropriate change in the MORT literature concerning the identification of causal factors. In a November 1994 publication titled Guideline to Use of the Management Oversight and Risk Tree, this appears under Performance Errors ... 

Emphasizes that a reasoned approach is needed for the identification of causal factors deriving from less than adequate policies, standards, procedures, and accountability systems, or their implementation practices, that impact on the aspects of safety, encompassing... 

If hazard identification and analysis do not relate to actual causal factors, the resulting corrective actions proposed will be misdirected and ineffective. A superior quality of incident investigation is required to identify and evaluate actual causal factors so that appropriate corrective actions can be taken. 

Although not necessarily intended, such report formats lead to identification of a single causal factor, usually the unsafe act, rather than stressing the concept of multiple causation. Sometimes—but only sometimes — a contributory causal factor was also identified. 

Five of the 15 forms received require entry of codes for causal factors, incident types, and injury t)q)es. When computer analysis programs first became available, I had been an aggressive promoter of the entiy of causal factor codes for later analysis. That proved to be inappropriate because accurate causal data are often not included in supervisors investigation reports or in insurance claims reports. Now, I recommend that computer-based analysis systems not include provision for causal data entry. They serve analysis purposes quite well for types of accidents, injury types, parts of body injured, and identification data (location, age, job title, etc.). 

A systematic approach to incident investigation, a proper identification of causal factors, and a follow-through on the implementation of corrective actions is essential to a good safety management and engineering system. These incident investigation concepts and procedures are to... 

The persons are selected on a stratified random sampling basis, with stratifications designated according to the type of exposure, quantity of exposure, degree of hazard present, and other criteria considered important to the representativeness of the sample. The objective is to discover causal factors that are critical, that is, that have contributed to an accident or potential accident situation. The unsafe acts and unsafe conditions identified by this method then serve as the basis for the identification of accident potential problem areas and the ultimate development of countermeasures designed to control accidents at the no-loss stage [p. 304],... 

The article (Rooney Vanden Heuvel, 2004) uses the term Root Cause Map as an equivalent to the term predefined tree, when the fourth step of the method B of root cause analysis is discussed. According to the article, root cause identification involves the use of a decision diagram called the Root Cause Map to identify the underlying reason or reasons for each causal factor . Fig. 3 shows a small part of a specific Root Cause Map that is reproduced from (CCPS, 2003). It is a subtree of larger decision tree. Displayed part helps the investigator identify detail causes in the SMS, namely, in a fraction of its component (iii) operation control. 

Root cause identification connects the specific chains of underlying causes from causal factor chart to generic chains of underlying causes from the Root Cause Map. Final nodes of the generic chains represent the most accurate causes in the safety management system. 

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