How to Create a Fault Tree Analysis Diagram (FTD)

Root cause analysis (RCA) tree diagram lets identify the root causes for a factor and then list possible corrective action. The diagram displays the structure of causes for a factor and possible corrective actions. The root cause analysis tree diagram is used for further formulation of actions.
"Tree Diagram.
This tool is used to break down broad categories into finer and finer levels of detail. It can map levels of details of tasks that are required to accomplish a goal or solution or task. Developing the tree diagram helps one move their thinking from generalities to specifics." [Seven Management and Planning Tools. Wikipedia]
This root cause analysis tree diagram template for the ConceptDraw PRO diagramming and vector drawing software is included in the Seven Management and Planning Tools solution from the Management area of ConceptDraw Solution Park.

"Failure analysis is the process of collecting and analyzing data to determine the cause of a failure. It is an important discipline in many branches of manufacturing industry, such as the electronics industry, where it is a vital tool used in the development of new products and for the improvement of existing products. There are many companies which provide services to find the cause of failure in products, devices and in post disaster situations. The failure analysis process relies on collecting failed components for subsequent examination of the cause or causes of failure using a wide array of methods, especially microscopy and spectroscopy. The NDT or nondestructive testing methods (such as Industrial computed tomography scanning) are valuable because the failed products are unaffected by analysis, so inspection always starts using these methods." [Failure analysis. Wikipedia]
The example "Audit failure - Fault tree analysis diagram" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Fault Tree Analysis Diagrams solution from the Engineering area of ConceptDraw Solution Park.

The FTA diagram sample "Fault tree analysis - Insulin delivery system" was redesigned from the illustration of "CMSI 641: Introduction to Software Engineering. Design of Critical Systems. B.J. Johnson. 2005. Loyola Marymount University".
"Another way of assessing hazards is using fault tree analysis. In this process, each of the identified hazards is covered by a detailed analysis to find out what might cause it. Either inductive or deductive reasoning is applied. In the case of software hazards, the usual focus is to determine faults that will cause the system to fail to deliver a system service, such as a monitoring system. A "fault tree" is constructed to link all the possible situations together, to help identify the interrelationships of the failures, which modules may cause them, and what "trickle-down effects" there might be. Here is an example of a fault tree, as applied to the Insulin delivery system from Sommerville...
Note that this tree is only partially complete, since only the potential software faults are shown on the diagram. The potential failures involving hardware, such as low battery, blood monitor or sensor failure, patient over-exertion or inattention, or medical staff failure are noticeable by their absence.
The fault tree and safety specification processes are two ways of helping with system risk assessment tasks. Once the risks are identified, there are other assessments that need to take place. First, the likelihood of the risk occurrance must be assessed. This is often quantifiable, so numbers may be assigned based on things like MTBF, latency effects, and other known entities. There may be other non-quantifiable contributors to the risk likelihood, however, such that these must be assessed and estimated by experts in the domain. (Don't short-change this process when dealing with critical systems!) Finally, the risk assessment must include the severity of the risk, meaning an estimation of the cost to the project in the event the risk item actually does occur. "Cost to the project" means all associated costs, including schedule delays, human injury, damage to hardware, corruption of data, and so on."
[myweb.lmu.edu/ bjohnson/ cmsi641web/ week15-2.html]
The FTA diagram example "Fault tree analysis - Insulin delivery system" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Fault Tree Analysis Diagrams solution from the Engineering area of ConceptDraw Solution Park.

"Root cause analysis (RCA) is a method of problem solving that tries to identify the root causes of faults or problems.
RCA practice tries to solve problems by attempting to identify and correct the root causes of events, as opposed to simply addressing their symptoms. Focusing correction on root causes has the goal of preventing problem recurrence. RCFA (Root Cause Failure Analysis) recognizes that complete prevention of recurrence by one corrective action is not always possible.
Conversely, there may be several effective measures (methods) that address the root causes of a problem. Thus, RCA is an iterative process and a tool of continuous improvement.
RCA is typically used as a reactive method of identifying event(s) causes, revealing problems and solving them. Analysis is done after an event has occurred. Insights in RCA may make it useful as a preemptive method. In that event, RCA can be used to forecast or predict probable events even before they occur. While one follows the other, RCA is a completely separate process to Incident Management." [Root cause analysis. Wikipedia]
The root cause analysis (RCA) tree diagram example "Manufacturing problem solution" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the solution "Seven Management and Planning Tools" from the Management area of ConceptDraw Solution Park.

"Subjective performance evaluation allows the use of a subtler, more balanced assessment of employee performance, and is typically used for more complex jobs where comprehensive objective measures are difficult to specify and/ or measure. Whilst often the only feasible method, the attendant problems with subjective performance evaluation have resulted in a variety of incentive structures and supervisory schemes. One problem, for example, is that supervisors may under-report performance in order to save on wages, if they are in some way residual claimants, or perhaps rewarded on the basis of cost savings. This tendency is of course to some extent offset by the danger of retaliation and/ or demotivation of the employee, if the supervisor is responsible for that employee’s output. ...
Another problem relates to what is known as the "compression of ratings". Two related influences—centrality bias, and leniency bias—have been documented ... The former results from supervisors being reluctant to distinguish critically between workers (perhaps for fear of destroying team spirit), while the latter derives from supervisors being averse to offering poor ratings to subordinates, especially where these ratings are used to determine pay, not least because bad evaluations may be demotivating rather than motivating. However, these biases introduce noise into the relationship between pay and effort, reducing the incentive effect of performance-related pay. ... this is the reason for the common separation of evaluations and pay, with evaluations primarily used to allocate training.
Finally, while the problem of compression of ratings originates on the supervisor-side, related effects occur when workers actively attempt to influence the appraisals supervisors give, either by influencing the performance information going to the supervisor: multitasking (focussing on the more visibly productive activities...), or by working “too hard” to signal worker quality or create a good impression...; or by influencing the evaluation of it, e.g., by "currying influence"... or by outright bribery..." [Principal–agent problem. Wikipedia]
The example "Person demotivated by evaluation - Fault tree analysis diagram" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Fault Tree Analysis Diagrams solution from the Engineering area of ConceptDraw Solution Park.

"Root cause analysis (RCA) is a method of problem solving that tries to identify the root causes of faults or problems. ...
RCA (in steps 3, 4 and 5) forms the most critical part of successful corrective action, because it directs the corrective action at the true root cause of the problem. Knowing the root cause is secondary to the goal of prevention, but without knowing the root cause, it is not possible to determine what an effective corrective action for the defined problem would be. ...
3. Ask "why" and identify the causes associated with each step in the sequence towards the defined problem or event. "Why" is taken to mean "What were the factors that directly resulted in the effect?"
4. Classify causes into causal factors that relate to an event in the sequence and root causes, that if eliminated, can be agreed to have interrupted that step of the sequence chain.
5. Identify all other harmful factors that have equal or better claim to be called "root causes." If there are multiple root causes, which is often the case, reveal those clearly for later optimum selection." [Root cause analysis. Wikipedia]
This root cause analysis (RCA) tree diagram example "Sale problem solution" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Seven Management and Planning Tools solution from the Management area of ConceptDraw Solution Park.

The accident analysis diagram example "Accident analytic tree" was redesigned from the picture 7-14 from the "DOE Workbook. Conducting Accident Investigations. Revision 2."
"Analytic tree analyses are well defined, useful methods that graphically depict, from beginning to end, the events and conditions preceding and immediately following an accident. An analytic tree is a means of organizing information that helps the investigator conduct a deductive analysis of any system (human, equipment, or environmental) to determine critical paths of success and failure. Results from this analysis identify the details and interrelationships that must be considered to prevent the oversights, errors, and omissions that lead to failures. In accident investigations, this type of analysis can consist of both failure paths and success paths, and can lead to neutral, negative, or positive conclusions regarding accident severity.
TIP.
An analytic tree enables the user to:
(1) Systematically identify the possible paths from events to outcome.
(2) Display a graphical record of the analytical process.
(3) Identify management system weaknesses and strengths."
[homer.ornl.gov/ sesa/ corporatesafety/ aip/ docs/ workbook/ Rev2/ chpt7/ chapt7.htm]
The FTA diagram example "Accident analytic tree" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Fault Tree Analysis Diagrams solution from the Engineering area of ConceptDraw Solution Park.