The Application of an Expanded Accident Sequence Model to Forensic Human Factors

Abstract

There are several models that assist the human factors specialist in identifying those behaviors that most likely contributed to an accident's occurrence. Of particular importance to forensic human factors specialists are models that can also serve as demonstrative aids in communicating the bases of their opinions to jurors. One such aid is a version of Ramsey's (1978) accident sequence model. The model, which has been expanded by the author, traces sequentially the activities that likely take place within the individual before an accident occurs. The expanded model prompts the investigator to ask the following questions: (1) Was the hazard detected? (2) If so, was it identified? (3) If correctly identified, were its characteristics perceived accurately? (4) If perception was veridical, was the individual alert to the danger? (5) If alert to the danger, did they appreciate the degree of risk involved? (6) If their assessment of risk was realistic, did the individual want to avoid the hazard? 7) And if they sought to avoid the hazard, could they to do so under the existing conditions? The author draws from cases in which he served as an expert witness to illustrate the model's application.