Forms of Root Cause Analysis
Accidents are rarely simple and almost never result from a single cause. Accidents may develop from a sequence of events involving performance errors, changes in procedures, oversights, and missions. Events and conditions must be identified and examined to find the cause of the accident and a way to prevent that accident and similar accidents from occurring again. By creating an event in the causal factor chain, multiple causes can be visually illustrated, and a visual relationship between the direct and contributing causes can be shown. Event causal charting also visually delineates the interactions and relationships of all involved groups or individuals. By using root cause analysis, one can develop an event causal chain to examine the accident in a step-by-step manner by looking at the events, conditions, and causal factors chronologically, to prevent future accidents.
Root cause analysis is used when there are multiple problems with a number of causes of an accident. A root cause analysis is a sequence of events that shows, step by step, the events that took place in order for the accident to occur. Root cause analysis puts all the necessary and sufficient events and causal factors for an accident in a logical, chronological sequence. It analyzes the accident and evaluates evidence during an investigation. It is also used to help prevent similar accidents in the future and to validate the accuracy of preaccidental system analysis. It is used to help identify an accident's causal factors, which, once identified, can be fixed to eliminate future accidents of the same or of similar nature.
On the downside, root cause analysis is a time-consuming process and requires the investigator to be familiar with the process for it to be effective. Investigators may need to revisit an accident scene multiple times and look at areas that are not directly related to the accident to have a complete event and causal factor chain. Analysis requires a broad perspective of the accident to identify any hidden problems that would have caused the accident.
One of the simplest root cause analysis techniques is to determine the causes of accidents/ incidents at different levels. During any hazard analysis, investigators are always trying to determine the root cause of any accident or incident. Experts who study accidents often do a breakdown or analysis of the causes. They analyze them at three different levels:
- 1. Direct causes (unplanned release of energy or hazardous material)
- 2. Indirect causes (unsafe acts and unsafe conditions)
- 3. Basic (root) causes (management safety policies and decisions, and personal factors)
When basic causes are eliminated, unsafe acts and unsafe conditions may not occur.
Thus, accidents have many causes. Basic (root) causes lead to unsafe acts and unsafe conditions (indirect causes). Indirect causes may result in a release of energy or hazardous material (direct causes). The direct cause may allow for contact, resulting in personal injury, property damage, or equipment failure (accident).