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Human Error Assessment and Reduction Technique


The Human Error Assessment and Reduction Technique (HEART) is a quantitative Human Reliability Assessment tool developed by J Williams and is a industry recognised methodology for quantifying human factors for use in risk analysis.


The HEART technique is a well-established method for human reliability assessment. It’s basis focuses on the factors that have a significant effect on an individual’s performance. It is fairly straight forward, easily understood and appropriately used to assess both physical and mental tasks.

The first stage of HEART requires that the task being performed is identified as one of 9 generic task types.

The next stage is to identify error-producing conditions (EPC), which are evident in the scenario and have a negative influence on human performance. There are 38 EPC’s that are modifying factors on the nominal level of human error probability and by applying a proportion of affect for each EPC selected a calculation an be made to derive a Human Error Probability. There is some subjectiveness in the application of the proportion of affect and as such the team carrying out the assessment have to agree the proportion factor applied based on the individual scenario


ProSalus use the HEART technique in LOPA and FTA assessments where the clients don’t have pre-defined Human Error Probabilities for use in risk analysis for a given task.