Who-What-Where-When-How Analysis
This traditional analysis technique is primarily used in accident investigation to determine the surface cause(s) of the accident.
Surface causes are the unique conditions and behaviors that contributed to or caused the accident.
The technique involves asking a series of initial 'who, what, where, when, and how' questions to identify the basic surface causes of an accident. While all types of questions are important, focusing on 'what,' 'where,' and 'how' is considered most effective in uncovering the immediate, observable surface causes of an accident.
Are individuals or groups getting hurt over and over, and is it the same kind of injury?
- Are only new employees getting hurt?
- Are only forklift and truck drivers having accidents?
- Are most of the accidents happening to younger or older workers?
- Is there an obvious trend indicating that particular departments are having most of the accidents?
Be careful when using this line of questioning. Focusing on "who" may be perceived by those being interviewed as an attempt to determine who is at fault or liable for the accident. Witnesses and others are more likely to withhold important information if they believe you are "going after them." Additionally, focusing on who was responsible or involved early in the investigation process may not be as relevant as understanding the basic facts of what occurred, where it happened, and how it took place.
This question looks for the basic cause of the physical trauma to the body. This might be best answered by determining trends in the following accident types:
- Struck by: A person is forcefully struck by an object. The force of the contact is provided by the object. Example: Struck by a falling object.
- Struck against: A person forcefully strikes an object. The person provides the force or energy. Example: Running up against a wall.
- Fall from elevation: A person slips or trips and falls to a level below the one they were walking or standing on. Example: Fall over edge while shingling roof.
- Fall to surface: A person slips or trips and falls to the surface they are working or standing on. Example: Fall due to slippery floor.
- Contact with: A person contacts a harmful substance or material. The person initiates the contact. Example: Contacting electricity.
- Contact by: Contact by a substance or material that, by its very nature, is harmful and causes injury or illness. Example: Acid splashes on a person's face.
- Caught on: A person is caught on an object that is either moving or stationary. This may cause the person to lose their balance and fall, be pulled into a machine, or suffer other harm. Example: A person is dragged into a machine because loose clothing is caught on a conveyor belt.
- Caught in: A person is trapped or otherwise caught in an opening or enclosure. Example: A person's arm is stuck in a printing machine when it starts up and causes injury.
- Caught between: A person is crushed, pinched, or otherwise caught between a moving and a stationary object, or between two moving objects. Example: A person bends over to plug in a tool and strains their back.
- Bodily reaction: Caused solely by stress imposed by the free movement of the body or assumption of a standard or unnatural body position. Example: Person bends over to plug in a tool and strains back.
- Over-exertion: A person over-extends or strains beyond their ability to lift, lower, push, or pull an object. Example: A person strains back while lifting a box.
- Over-exposure: Over time, a person is exposed to harmful energy, such as noise, heat, toxic chemicals, or hazardous atmospheres. Example: A person loses consciousness due to lack of oxygen.
- Are they getting hurt while doing their regular job, or are they working in another department when they get hurt?
- Are workers getting injured more in certain departments or areas of the workplace, such as the maintenance shop or on towers?
- Are workers only involved in accidents in particular facility locations, such as the warehouse, high traffic areas, or the parking lot?
Look for trends if employees work in shifts:
- A particular time of the day: Early or late in the work shift?
- A particular day of the week: Mondays? Fridays?
- A particular week of the month: Just before payday? Last production week?
- A particular month of the year: December?
- A particular quarter of the year: Last fiscal quarter?
- A particular season of the year: Just before hunting season?
- A particular business cycle: Just before the annual report?
This question is directed toward hazardous conditions and unsafe work practices.
- Were hazardous materials, tools, or equipment used?
- What personal protective equipment was the worker not using?
- Are work shifts too long?
- Were workers using unsafe practices?
- Are workers getting hurt as a result of factors within or outside of work?
- Were workers using unsafe practices? Are workers getting hurt due to factors within or outside of work: factors the employer controls or can't control?
Knowledge Check Choose the best answer for the question.
6-6. Which type of questions are the most important to discover the surface causes of accidents?
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