Which method is commonly used in root cause analysis?

Which method is commonly used in root cause analysis?

• A. Randomized controlled trials
• B. Cost-benefit analysis
• C. Meta-analysis
• D. Five Whys

Answer: (D)

Drilling down to the underlying cause by repeatedly asking why is the method being tested here. The Five Whys guides teams to peel away symptoms and uncover the root cause by asking why several times—often about five rounds, though it can vary—until a fundamental process or system factor is identified that, when fixed, would prevent recurrence. This approach is valued for being simple, fast, and collaborative, helping groups challenge assumptions rather than stopping at a first, surface-level explanation. For example, if a machine stops, you ask why it stopped, why the fuse blew, why the motor drew excess current, why the bearing wore, why lubrication was insufficient, and so on. This chain can reveal gaps in maintenance or process design that, once addressed, reduce the chance of the problem returning. In contrast, randomized controlled trials are designed to test whether an intervention works under controlled conditions, not to diagnose why a problem occurred. Cost-benefit analysis weighs economic costs and benefits to inform decision-making, not to trace causation. Meta-analysis combines results from multiple studies to estimate overall effects, which is about evidence synthesis rather than pinpointing a root cause.

Drilling down to the underlying cause by repeatedly asking why is the method being tested here. The Five Whys guides teams to peel away symptoms and uncover the root cause by asking why several times—often about five rounds, though it can vary—until a fundamental process or system factor is identified that, when fixed, would prevent recurrence. This approach is valued for being simple, fast, and collaborative, helping groups challenge assumptions rather than stopping at a first, surface-level explanation. For example, if a machine stops, you ask why it stopped, why the fuse blew, why the motor drew excess current, why the bearing wore, why lubrication was insufficient, and so on. This chain can reveal gaps in maintenance or process design that, once addressed, reduce the chance of the problem returning.

In contrast, randomized controlled trials are designed to test whether an intervention works under controlled conditions, not to diagnose why a problem occurred. Cost-benefit analysis weighs economic costs and benefits to inform decision-making, not to trace causation. Meta-analysis combines results from multiple studies to estimate overall effects, which is about evidence synthesis rather than pinpointing a root cause.