Risk Estimation

‍Risk Estimation is the systematic act of scoring a potential quality issue by assessing two primary factors: the severity of the possible resulting harm and the probability that the harm will occur. This process yields a measurable output, often referred to as a risk index, which represents the overall risk level before any mitigation actions are considered.

Risk Estimation transforms the list of theoretical problems identified in the initial analysis into quantifiable data points needed for risk evaluation and control.

Core Components of Risk Estimation

The term Risk Estimation is the crucial analytical process of assigning a measurable value to potential harms identified during Risk Analysis, thereby quantifying the severity and likelihood of a specific hazardous situation.

Risk estimation is integral to the mandatory risk management process in regulated industries.

Process of Quantification: Risk estimation is the procedure used to assign a numerical value to the various possibilities (hazards) identified during the risk analysis phase.

Metrics Considered: To determine the risk level, the estimation process must consider both the probability of occurrence of the harm and the severity of the harm.

Resulting Risk Index: The result of this process is the risk associated with a given hazardous situation. This risk can be numerical or translated onto a qualitative scale (e.g., low, medium, high), and is often referred to as a risk index level.

Goal: The overall intent of performing a risk analysis (which includes estimation) is to calculate risk under normal and fault conditions.

Methodology and Data Support

The risk estimation process must be grounded in objective data to be useful for the quality management system.

Qualitative vs. Quantitative: Risk estimation may be conducted qualitatively or quantitatively, or by using a mix of both methods.

Documentation for Qualitative Systems: If an organization employs a qualitative system (such as assigning high, medium, or low risk), the definitions of these categories must be clearly established and documented within the risk management documentation.

Data Requirement: Even qualitative estimations need to be supported by data or information to validate the assessment. Sources for this data can include:

• Publicly available information, such as incident reports or published literature regarding similar existing devices.
• Reports from pre-market testing, clinical trial, or usability testing data.
• Opinions provided by expert consultants, provided their qualifications are documented within the quality system.

Timing and Relationship to Other Risk Processes

Risk estimation fits sequentially between hazard identification and risk evaluation.

Timing: Risk estimation is applied after the cross-functional team has generated the initial list of hazards and hazardous situations (Risk Analysis).

Prerequisite Criteria: The methodology for calculating the risk index number and the risk acceptability criteria must be defined BEFORE the risk analysis and estimation begin, to ensure the process remains as objective as possible.

Exclusions: The estimation phase focuses solely on calculating the inherent risk; it does not look at the acceptability of the risk levels determined, nor does it consider any risk control measures (mitigations) that will be applied later.

Analogy for Understanding Risk Estimation

If Risk Analysis is the process of building a comprehensive list of every potential danger in a medical device (e.g., "The battery could fail," "The user might press the wrong button"), Risk Estimation is the scorekeeper who assigns quantifiable metrics to each danger.

It takes the danger (e.g., "The user might press the wrong button") and asks: "Based on historical data and testing (data support), how likely is this mistake (probability)? And if it happens, how bad is the outcome (severity)?" By multiplying or combining these two scores, it outputs a single, objective Risk Index (e.g., a score of 18 out of 25). This score is the raw, unmitigated threat level that the management team must then evaluate and decide whether to accept or control.

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