In complex operational environments, where risk is constant, the interaction between human, technological, and environmental factors creates a challenging scenario for safety.
Although processes and technologies are constantly evolving, the human element – with its variations in attention, susceptibility to fatigue, and fluctuations in performance – remains a critical factor in safety. James Reason’s (1990) “Swiss cheese” model illustrates how accidents occur when multiple failures, including human errors, align across layers of defense.
In this context, HEART (Human Error Assessment and Reduction Technique) emerges as an innovative tool to assess and mitigate the risk of human error. Developed to be rigorous and practical, HEART consists of several interconnected steps that together offer a comprehensive analysis of the potential for human error.
What is HEART?
HEART is a technique developed to be rigorous and practical, consisting of several interconnected steps that offer a comprehensive analysis of the potential for human error. The application of the method allows us to quantify the chance of human error in each of the analyzed activities.
Its structure is based on four main steps:
- Generic Task Types: Categorization of operational activities into standardized task types.
- Error Producing Conditions: Identification of factors that may increase the probability of human errors.
- Assessed Proportion of Affect: Estimation of the impact of each error-producing condition on the task in question.
- Calculate Human Error Probability: Quantitative determination of the probability of human error occurrence for each analyzed task. These steps provide a holistic and structured approach to identify and quantify the risk of human error, allowing safety managers to take action to reduce such risks.
HEART in Practice: The NASA Case
The effectiveness and relevance of HEART have been widely recognized by various high-risk organizations around the world. A notable example is NASA, which used HEART in its ground processing operations. A study conducted by Tiffaney Miller Alexander, PhD (2016), titled “Human Error Assessment and Reduction Technique (HEART) and Human Factor Analysis and Classification System (HFACS),” investigated the application of HEART in NASA’s complex operations. The study:
- Validated the applicability of HEART in highly complex operational environments
- Demonstrated its ability to identify factors contributing to errors
- Showed how HEART can assess the impact of these factors and predict probabilities of future errors
- Evidenced HEART’s adaptability to other operational contexts
The Value of HEART
The value of HEART lies in its ability to quantify the risk of human error in a systematic and evidence-based manner. By categorizing tasks, identifying conditions that can lead to errors, and calculating probabilities, HEART offers managers and safety professionals valuable insights to improve processes, train teams, and implement preventive measures.
Its flexibility allows for adaptation to various sectors and operational contexts. Whether in the aerospace, nuclear, petrochemical, Oil and Gas industries, or any other environment where human error can have significant consequences, HEART provides a robust framework for risk analysis and mitigation.
HEART and Innovation: Cognittiv’s Approach
Recognizing the value and versatility of HEART, Cognittiv integrates this method into its neuroergonomic assessment. Combining the principles of HEART with insights from neuroscience, Cognittiv’s analysis:
- Calculates a risk percentage per function
- Uses this percentage to calibrate its cognitive readiness system
Crucial HEART Steps
Task Analysis (Generic Task Types)
The first crucial step of HEART is Task Analysis, also known as the categorization of Generic Task Types. In this phase, the goal is to break down complex operational activities into more manageable and standardized components. HEART identifies nine generic task categories, each associated with a nominal probability of human error:
- Totally familiar, carried out rapidly or with little need for attention.
- Tasks requiring a change or restoration of the system to a new or original state.
- Complex tasks requiring a high level of understanding and skill.
- Quite simple tasks, carried out rapidly or with little attention.
- Routine, highly practiced, rapid tasks involving low skill.
- Tasks requiring restoration or change of the system, following procedures with some checking.
- Completely new tasks, performed in real emergency situations.
- Tasks requiring correct interpretation of a system display, without guidance.
- Tasks that do not allow verification or require absolute judgment.
This categorization not only provides a basis for risk analysis but also allows for comparisons between different operations and sectors.
Error Producing Conditions (EPCs)
The second step is the identification of Error Producing Conditions (EPCs). These are environmental, personal, or task-related conditions that can increase the probability of human error. HEART identifies 43 EPCs, each with a multiplier representing the degree of impact on error.
Some examples of EPCs include:
- Unfamiliarity with a situation
- Shortage of time for error detection and correction
- Information overload
- Operator fatigue
The identification of EPCs allows for a contextualized risk analysis, providing valuable insights for error mitigation through adjustments in environments or procedures.
Assessed Proportion of Affect (APoA)
The third step, the Assessed Proportion of Affect (APoA), refines the analysis by considering the degree to which each Error Producing Condition (EPC) affects the task. This process recognizes that not all conditions will have the same impact in all situations. The APoA adjusts the influence of each EPC according to its actual effect on the specific task being analyzed.
This adjustment is crucial for making the analysis more realistic and accurate. It avoids exaggerations in risk estimation when a condition has little actual impact and also prevents underestimations when a condition is particularly influential in a given task.
Human Error Probability Calculation
The final step of the HEART process is the calculation of the Human Error Probability (HEP). This calculation combines the basic probability of error associated with the task type with the adjusted effects of the identified Error Producing Conditions. The result is a quantitative estimate of the risk of human error for the specific task being analyzed. This estimate takes into account both the nature of the task and the specific conditions under which it is performed.
The calculation method used in HEART considers the complex interactions between the different factors contributing to human error. This results in a more accurate and nuanced risk assessment than would be possible with simpler methods. The final result is expressed as a probability, indicating the estimated chance of a human error occurring in the execution of the analyzed task. This information is valuable for managers and safety professionals, as it allows them to prioritize risk mitigation efforts and implement preventive measures where they are most needed.
Conclusion
HEART has proven to be an excellent tool in assessing and reducing human errors in complex operations. Its 30 years of studies and recognition by NASA demonstrate its relevance. By adopting HEART, organizations can systematically identify, prioritize, and mitigate risks, significantly elevating their safety standards.
