Getting to the Facts: Five-Why Analysis
This technique is used once you have asked the who-what-where-when-how questions discussed in the previous section.
The "5 Whys" Problem-Solving Method
In this technique, we list each of our analysis findings and then continue by asking "why" at least five times for each finding. Doing this will help us eventually arrive at one or more root causes contributing to the accident.
Let's apply the who-what-where-when-how analysis technique to an accident summary statement to determine surface causes and then use the 5-Why analysis to determine the accident's root causes.
Finding: Bob, a new hire in the finish department, was injured as he attempted to remove a jammed piece of wood from a conveyor belt under a large piece of equipment.
Who got hurt? Bob, a new hire.
- Why? Bob was the only worker available to do the job.
- Why? The shift was understaffed.
- Why? Management has reduced staffing.
- Why? Sales have decreased in the last two quarters.
- Why? Increased competition.
What was he doing? Removing a piece of wood jammed in a conveyor belt.
- Why? Bob thought it was his job, and his supervisor expected it.
- Why? Bob was not properly trained or briefed by the supervisor.
- Why? The supervisor did not train or properly brief Bob.
- Why? The company does not have electrical safety training, machine guarding safety, or lockout/tagout procedures.
- Why? The company does not have a formal safety training program.
Where did the accident happen? Within energized equipment in the finish department.
- Why? The wood had jammed the conveyor within the energized equipment.
- Why? The wood had slipped through the side of the belt into the pulley system.
- Why? The conveyor system does not have adequate guarding along the length of the system.
- Why? The conveyor system has been used for 40 years and did not have proper guarding when purchased.
- Why? Guards were not mandated by standards when purchased.
When did the accident happen? At 3:00 am on the mid shift.
- Why? That is when the wood became lodged in the conveyor system.
- Why? The equipment was not being monitored during the mid shift.
- Why? The mid shift was understaffed.
- Why? The company has difficulty hiring workers for the mid shift.
- Why? Employees receive no incentives for working the mid shift.
How did he get hurt? His hand was caught and pinched by an incoming nip point on the moving conveyor.
- Why? The conveyor was in operation when Bob attempted to remove the wood.
- Why? Bob did not perform lockout/tagout before removing the guard and reaching into the conveyor belt area.
- Why? Bob did not realize he needed to deenergize the equipment before removing the wood.
- Why? Bob did not receive machine guarding, electrical safety, or lockout/tagout training.
- Why? The supervisor did not ensure Bob received proper training before the assignment.
As you can see, the first set of questions addresses the surface causes for the accident. Once we know what directly caused the injury or illness, we begin to ask why to arrive at the root causes. Remember, each time a why question is asked, a deeper root cause is uncovered. To get to the deep root causes, ask why at least five times.
Knowledge Check Choose the best answer for the question.
6-7. What is the purpose of the 5-Why analysis?
You forgot to answer the question!