Unsafe acts and unsafe conditions: Development of a prelude model

Construction safety management has long utilised the concepts of unsafe acts and unsafe conditions within incident and accident reporting processes. Unsafe acts are often considered to be the greater concern; with figures of approximately 80-90% of accidents attributed to unsafe worker behaviour, although unsafe conditions remain relevant. It has also been argued that both play a part in safety, as manifest in highly complex accident causation models, yet industry often remains reliant on the simplistic categorisations of acts/conditions within accident reporting processes and safety observations undertaken in practice. This utility and common practice must be recognised, and it can be suggested that acts and conditions are firmly interlinked. Drawing on a large dataset of nearly 4,000 Safety Observation Reports from a large infrastructure construction project, investigation of the way in which incidents are categorised is explored and then, via content analysis of a purposive sample of individual reports, the reality of how the acts and conditions combine and interrelate is evaluated. Findings revealed significant inconsistency in the application of the categorisations of act or condition, and utilisation of the process to apportion individual blame through ‘unsafe acts’. Grounded in the data, a conceptual model is developed that recognises the state of ‘unsafety’ of both acts and conditions, but also explores the preludes to both. It can be suggested that within the construction context there are relatively few precursors that produce unsafe acts or conditions in practice, and employing these in practice would provide greater insights, enhancing utility without adding significant complexity. Integration of this model within the reporting process would enable management to better use reporting data in the development and implementation of focused interventions, albeit still grounded in the familiar unsafe acts and unsafe conditions identified on their projects