Why “Knowledge-Based Decision” Isn’t Always About Knowing More

I find that the term “knowledge-based decision” on the TapRooT® Root Cause Tree® is sometimes confusing to students and new TapRooT® Investigators. It often sounds like a fancy way of saying, “the worker didn’t know enough.” But that’s not quite right.

Let’s break it down.

The Three Levels of Human Decision-Making

Human performance research (including the work of Rasmussen and Reason) identifies three levels of decision-making:

1. Skill-based – actions performed automatically and intuitively, like tying your shoes.
2. Rule-based – following established procedures, like using a checklist or SOP.
3. Knowledge-based – situations where neither skills nor rules apply, and the worker must analyze the situation, diagnose the problem, and decide what to do based on experience or reasoning.

Rather than blaming individuals for mistakes, this model encourages us to examine whether the system supported the appropriate type of decision-making. Was the task routine and intuitive, guided by a rule, or entirely dependent on the worker’s personal judgment?

So What is a Knowledge-Based Decision?

A knowledge-based decision happens when a worker is in a novel, unfamiliar, or complex situation, where there are no clear procedures, no previous training that directly applies, and no obvious cues. They must rely on critical thinking, judgment, and problem-solving in real time.

Examples:

• A nurse encounters a rare medication interaction not covered by protocols.
• A technician faces an unexpected equipment behavior with no troubleshooting guide available.
• A pilot must land a plane with multiple system failures that were never trained for together.

In these cases, the worker is forced to think their way through the problem, not because they lacked knowledge, but because the system didn’t provide that level of structure, guidance, or tools for that situation.

Common Misconception: “They Just Didn’t Know Enough”

It’s easy to confuse knowledge-based decisions with ignorance or poor training. But if a task:

• Is typically guided by a checklist or standard procedure,
• Has been trained for under normal operating conditions,
• Or can be made intuitive with better design…

…then it’s not a knowledge-based decision.

Instead, the root cause may lie in training NI, procedure NI, human engineering, or even oversight/accountability NI, not the worker’s knowledge.

When analyzing human errors:

• Don’t assume a decision was knowledge-based just because it led to a mistake.
• Ask: “Was the person put in a situation where they had no tools or guidance to rely on?”
• If the task could have been supported by design, procedures, or training, then that’s where the system needs to improve.

TapRooT® RCA helps us investigate beyond the surface and see the true nature of decision-making. Blaming a person for using their judgment in a judgment-required situation misses the point and the root cause.

Root Cause Rookie or Expert? There’s More to Learn.

The 5-Day TapRooT® Advanced Root Cause Analysis Team Leader Training goes far beyond basic investigation skills. In this course, you’ll gain a deeper understanding of:

• the TapRooT® Root Cause Tree®
• how to use it effectively
• how to avoid common missteps, and choosing the wrong root causes (like “knowledge-based decisions”) for Causal Factors without evidence.

Learn how to correctly identify root causes that are often misunderstood and apply the TapRooT® System to real-world cases with precision. This training provides clarity, confidence, and competence in leading investigations that truly drive improvement.