When the Five Whys Finds the Wrong Root Cause

The Five Whys is one of the most widely taught root cause analysis tools in healthcare (Ohno, 1988; Serrat, 2017). The concept is simple: start with a problem and repeatedly ask “Why?” until the underlying cause is identified. Many introductory articles present the method as though it reliably uncovers the root cause after five questions. In practice, however, experienced investigators know something different.

The Five Whys does not automatically reveal root causes. It generates explanations. Whether those explanations are useful, incomplete, or entirely wrong depends on how the questioning is conducted and who participates in the discussion (Dekker, 2014; Rooney & Vanden Heuvel, 2004). Understanding the limitations of the method is often more important than understanding the mechanics.

The Same Event Can Produce Different Five Why Chains

Consider a medication administration error.

Problem: A patient received the wrong medication.

One team might develop the following chain:

1. Why did the patient receive the wrong medication?
   • The nurse selected the wrong medication.
2. Why did the nurse select the wrong medication?
   • The nurse was distracted.
3. Why was the nurse distracted?
   • The unit was busy.
4. Why was the unit busy?
   • Staffing levels were inadequate.
5. Why were staffing levels inadequate?
   • Several staff members called in sick.

A different team investigating the same event might produce an entirely different pathway:

1. Why did the patient receive the wrong medication?
   • The nurse selected the wrong medication.
2. Why did the nurse select the wrong medication?
   • The medications appeared similar.
3. Why did they appear similar?
   • Packaging was nearly identical.
4. Why was the packaging difficult to distinguish?
   • Storage practices placed look-alike medications together.
5. Why were they stored together?
   • No standardized storage policy existed.

Both chains are plausible, appear logical, and both cannot represent the complete explanation. This illustrates an important reality: Five Whys outcomes depend heavily on who is in the room, what information they possess, and what assumptions they bring to the discussion. The method often reveals a pathway to a cause, not necessarily the cause (Dekker, 2014; Hollnagel, 2014).

The Human Error Trap

One of the most common failure modes occurs when questioning stops at human performance. Investigators may conclude:

• The nurse forgot.
• The physician overlooked the result.
• The technician missed a step.
• The employee was distracted.

These explanations often feel satisfying because they identify a clear actor. Unfortunately, they rarely explain why the event occurred. People forget things every day; they become distracted every day; they miss steps every day. If the analysis ends there, little has been learned about the system conditions that made the error more likely. Human actions are often the starting point of an investigation, not the endpoint (Reason, 2000; Dekker, 2014).

A useful Five Why discussion should continue beyond individual behavior to explore workload, design, training, communication processes, equipment, environmental conditions, workflow design, and organizational factors (Reason, 2000; Carayon et al., 2006).

Beware of Dead-End Answers

Many Five Why analyses become stuck because the team accepts answers that sound like causes but do not generate actionable learning.

Common dead-end answers include:

• They forgot.
• They were busy.
• They were not paying attention.
• They did not follow policy.
• They made a mistake.
• They were careless.

These statements describe what happened. They do not explain why it happened (Rooney & Vanden Heuvel, 2004).

A useful test is to ask:

“If we fixed this answer, would we know what to change?”

For example:

Cause: The nurse forgot.

Potential response:
What would help people remember?

This question often uncovers more meaningful factors:

• Excessive interruptions
• Poor visual cues
• Competing priorities
• Workflow complexity
• Cognitive overload
• Inadequate reminders

The investigation can then move from blame toward system understanding (Reason, 2000; Dekker, 2014).

Confirmation Bias Can Shape the Entire Analysis

Five Why discussions are particularly vulnerable to confirmation bias (Kahneman, 2011). Teams often begin investigations with an implicit theory about what happened. Without realizing it, they may ask questions that support that theory.

For example:

• If leadership believes staffing is the issue, the questioning may naturally drift toward staffing explanations.
• If managers believe training is inadequate, the questioning may repeatedly arrive at training deficiencies.
• If clinicians believe technology is unreliable, technology may become the apparent root cause.

The danger is not that these explanations are wrong. The danger is that alternative explanations are never explored. The Five Whys can become less of an investigation and more of a structured justification for an existing belief (Nickerson, 1998; Kahneman, 2011).

Why Multiple Five Why Pathways Matter

Many healthcare events occur because several conditions interact simultaneously (Reason, 2000; Hollnagel, 2014).

A patient fall may involve:

• Environmental hazards
• Medication effects
• Staffing conditions
• Assessment processes
• Communication gaps
• Equipment issues

A single linear Five Why chain may capture only one branch of a much larger system. This is why experienced investigators often develop multiple Five Why pathways from the same event.

Instead of asking:

“What is the root cause?”

They ask:

“What contributing pathways may have led to this outcome?”

This shift often produces a richer understanding of the event and prevents premature closure (Hollnagel, 2014; Carayon et al., 2006).

The Most Important Question: What Evidence Supports This Answer?

A common weakness in Five Why exercises is that each answer is treated as fact. In reality, many answers are assumptions (Dekker, 2014).

For every “why,” investigators should ask:

• What evidence supports this conclusion?
• How do we know this is true?
• Could another explanation fit the available facts?
• What information would confirm or refute this hypothesis?

These questions transform the exercise from speculation into investigation (Rooney & Vanden Heuvel, 2004).

Using the Five Whys More Effectively

The Five Whys remains a valuable tool when used appropriately.

It works best when teams:

• Include multiple perspectives.
• Challenge assumptions.
• Continue beyond human error explanations.
• Avoid dead-end answers.
• Explore multiple causal pathways.
• Seek evidence for each conclusion.
• Treat findings as hypotheses requiring validation (Rooney & Vanden Heuvel, 2004; Serrat, 2017).

The goal is not to discover a single perfect root cause. The goal is to develop increasingly plausible explanations that can be tested and explored.

Key Takeaway

The Five Whys is often presented as a method for finding the root cause of a problem. In reality, it is better viewed as a hypothesis-generation tool (Rooney & Vanden Heuvel, 2004; Serrat, 2017). The answers produced by the method are shaped by the participants, the questions asked, the evidence available, and the assumptions made during the discussion.

Used thoughtfully, the Five Whys can open important lines of inquiry. Used uncritically, it can create the illusion of understanding while overlooking the true drivers of system performance (Dekker, 2014; Hollnagel, 2014). The strength of the Five Whys is not that it finds root causes. Its strength is that it helps investigators ask better questions.

References

Carayon, P., Schoofs Hundt, A., Karsh, B. T., Gurses, A. P., Alvarado, C. J., Smith, M., & Flatley Brennan, P. (2006). Work system design for patient safety: The SEIPS model. Quality & Safety in Health Care, 15(Suppl. 1), i50-i58.

Dekker, S. (2014). The field guide to understanding ‘human error’ (3rd ed.). Ashgate.

Hollnagel, E. (2014). Safety-I and Safety-II: The past and future of safety management. Ashgate.

Kahneman, D. (2011). Thinking, fast and slow. Farrar, Straus and Giroux.

Nickerson, R. S. (1998). Confirmation bias: A ubiquitous phenomenon in many guises. Review of General Psychology, 2(2), 175-220.

Ohno, T. (1988). Toyota production system: Beyond large-scale production. Productivity Press.

Reason, J. (2000). Human error: Models and management. BMJ, 320(7237), 768-770.

Rooney, J. J., & Vanden Heuvel, L. N. (2004). Root cause analysis for beginners. Quality Progress, 37(7), 45-53.

Serrat, O. (2017). The Five Whys technique. In Knowledge solutions: Tools, methods, and approaches to drive organizational performance (pp. 307-310). Springer.