ICH Q9(R1) emphasizes that knowledge is fundamental to effective risk management. The guideline states that “QRM is part of building knowledge and understanding risk scenarios, so that appropriate risk control can be decided upon for use during the commercial manufacturing phase.”
We need to recognize the inverse relationship between knowledge and uncertainty in risk assessment. ICH Q9(R1) notes that uncertainty may be reduced “via effective knowledge management, which enables accumulated and new information (both internal and external) to be used to support risk-based decisions throughout the product lifecycle”
In order to gauge the confidence in risk assessment we need to gauge our knowledge strength.
The Spectrum of Knowledge Strength
Knowledge strength can be categorized into three levels: weak, medium, and strong. Each level is determined by specific criteria that assess the reliability, consensus, and depth of understanding surrounding a particular subject.
Indicators of Weak Knowledge
Knowledge is considered weak if it exhibits one or more of the following characteristics:
- Oversimplified Assumptions: The foundations of the knowledge rely on strong simplifications that may not accurately represent reality.
- Lack of Reliable Data: There is little to no data available, or the existing information is highly unreliable or irrelevant.
- Expert Disagreement: There is significant disagreement among experts in the field.
- Poor Understanding of Phenomena: The underlying phenomena are poorly understood, and available models are either non-existent or known to provide inaccurate predictions.
- Unexamined Knowledge: The knowledge has not been thoroughly scrutinized, potentially overlooking critical “unknown knowns.”
Hallmarks of Strong Knowledge
On the other hand, knowledge is deemed strong when it meets all of the following criteria (where relevant):
- Reasonable Assumptions: The assumptions made are considered very reasonable and well-grounded.
- Abundant Reliable Data: Large amounts of reliable and relevant data or information are available.
- Expert Consensus: There is broad agreement among experts in the field.
- Well-Understood Phenomena: The phenomena involved are well understood, and the models used provide predictions with the required accuracy.
- Thoroughly Examined: The knowledge has been rigorously examined and tested.
The Middle Ground: Medium Strength Knowledge
Cases that fall between weak and strong are classified as medium strength knowledge. This category can be flexible, allowing for a broader range of scenarios to be considered strong. For example, knowledge could be classified as strong if at least one (or more) of the strong criteria are met while none of the weak criteria are present.

A Simplified Approach
For practical applications, a simplified version of this framework can be used:
- Strong: All criteria for strong knowledge are met.
- Medium: One or two criteria for strong knowledge are not met.
- Weak: Three or more criteria for strong knowledge are not met.
Implications for Decision-Making
Understanding the strength of our knowledge is crucial for effective decision-making. Strong knowledge provides a solid foundation for confident choices, while weak knowledge signals the need for caution and further investigation.
When faced with weak knowledge:
- Seek additional information or expert opinions
- Consider multiple scenarios and potential outcomes
- Implement risk mitigation strategies
When working with strong knowledge:
- Make decisions with greater confidence
- Focus on implementation and optimization
- Monitor outcomes to validate and refine understanding
Knowledge Strength and Uncertainty
The concept of knowledge strength aligns closely with the levels of uncertainty.
Strong Knowledge and Low Uncertainty (Levels 1-2)
Strong knowledge typically corresponds to lower levels of uncertainty:
- Level 1 Uncertainty: This aligns closely with strong knowledge, where outcomes can be estimated with reasonable accuracy within a single system model. Strong knowledge is characterized by reasonable assumptions, abundant reliable data, and well-understood phenomena, which enable accurate predictions.
- Level 2 Uncertainty: While displaying alternative futures, this level still operates within a single system where probability estimates can be applied confidently. Strong knowledge often allows for this level of certainty, as it involves broad expert agreement and thoroughly examined information.
Medium Knowledge and Moderate Uncertainty (Level 3)
Medium strength knowledge often corresponds to Level 3 uncertainty:
- Level 3 Uncertainty: This level involves “a multiplicity of plausible futures” with multiple interacting systems, but still within a known range of outcomes. Medium knowledge strength might involve some gaps or disagreements but still provides a foundation for identifying potential outcomes.
Weak Knowledge and Deep Uncertainty (Level 4)
Weak knowledge aligns most closely with the deepest level of uncertainty:
- Level 4 Uncertainty: This level leads to an “unknown future” where we don’t understand the system and are aware of crucial unknowns. Weak knowledge, characterized by oversimplified assumptions, lack of reliable data, and poor understanding of phenomena, often results in this level of deep uncertainty.
Implications for Decision-Making
- When knowledge is strong and uncertainty is low (Levels 1-2), decision-makers can rely more confidently on predictions and probability estimates.
- As knowledge strength decreases and uncertainty increases (Levels 3-4), decision-makers must adopt more flexible and adaptive approaches to account for a wider range of possible futures.
- The principle that “uncertainty should always be considered at the deepest proposed level” unless proven otherwise aligns with the cautious approach of assessing knowledge strength. This ensures that potential weaknesses in knowledge are not overlooked.
Conclusion
By systematically evaluating the strength of our knowledge using this framework, we can make more informed decisions, identify areas that require further investigation, and better understand the limitations of our current understanding. Remember, the goal is not always to achieve perfect knowledge but to recognize the level of certainty we have and act accordingly.







