Segmented point process models for work system safety analysis

This study proposes a new scheme for measurement of safety performance in work systems using segmented point process models that can capture the points of changes in the working conditions as well as changes in safety initiatives. Data, collected from an underground coal mine, were analyzed using homogeneous (HPP) as well as non-homogeneous (NHPP) point process models. Time between occurrences (TBO) and number of occurrences (NOC) were modeled followed by the development of loss functions. The methodology can be used to monitor safety performance and to check safety program effectiveness. The findings of the case study application showed that the injury occurrences data fit the models for (i) 'all incidents' and 'first aid' cases with one change point at 458 days, (ii) 'near-miss' case with one change point at 441 days, and (iii) 'minor' injury case with two-change points at 11 days and 375 days, respectively.